Beta-alanine as a Dual Modification Additive in Organic Solar Cells

ZAFAR　Saud uz， ZHANG　Weichao， YANG　Shuo， LI　Shilin， ZHANG　Yingyu， ZHANG　Yuan， ZHANG　Hong*， ZHOU　Huiqiong*

Beta-alanine as a Dual Modification Additive in Organic Solar Cells

ZAFARSaud uz1， ZHANGWeichao2， YANGShuo3， LIShilin2， ZHANGYingyu1， ZHANGYuan2， ZHANGHong1*， ZHOUHuiqiong1*

（，，，，100190，；，，100191，；，，101100，）

Beta-alanine； Additive； Dual-modification； Transporting layer； Organic solar cell

1 Introduction

In recent years， the efficiency of organic solar cells（OSCs）［1］has surpassed 19%［2］， owing to the emergence of non-fullerene acceptors（NFAs）［3］. While efforts to design new active［4，5］layer materials， optimize morphology［6］， and develop advanced device structures［7］， researchers are also exploring novel interfacial materials［8］， including 0D—3D materials［9］， self-assembled monolayers（SAMs）， organic compounds， and eco-friendly compounds［10—13］， to enhance the performance parameters of OSCs. These interfacial materials form new functional bond links［14］with the interface layer compounds and can significantly improve cell efficiency if optimized appropriately. To achieve better performance and properties in OSCs， it is crucial to optimize both the hole transport layer（HTL）［15，16］and electron transport layer（ETL） interface layers［17，18］. This can be accomplished by introducing ionic materials， polar compounds， zwitterions， and high-boiling materials into the interface layers［19—22］. However， classic interfacial materials such as poly（3，4-ethylenedioxythiophene）∶poly（styrenesulfonate）（PEDOT∶PSS）［23］and poly［9，9-bis（3′-（，-dimethyl）--ethylammoinium-propyl-2，7-fluorene）-alt-2，7-9，9-dioctylfluorene）］ dibromide（PFN-Br）［24］exhibit limitations. PEDOT∶PSS undergoes shortcomings including acidity（pH=1.5—2.5）［25］， hygroscopicity（absorbs moisture from the surrounding while preparing thin films）， anisotropic charge injection［26］， moderate conductivity， inhomogeneities in electronic and structural morphologies with batch-to-batch variation［27，28］， and for PFN-Br detrimental contact resistance arising from their interfacial properties［29］， scarcity of delocalized electrons， molecular aggregation of conjugated structure along with insulating properties［30—32］. The PFN-Br based devices also suffered from instability［33］， and mismatched energy levels between the cathode and acceptors. To overcome these drawbacks， the adoption of new materials or the use of additives is essential to attain higher efficiency OSCs.

In this study， beta-alanine（-alanine）［34］was employed as a small molecule additive with hydroxyl （—OH）/carboxyl group（—COOH） on one side and amine（—NH2）［35］on the other side， with a chemical formula of C3H7NO2. Despite its antioxidant properties［36］，-alanine has received limited attention in the context of organic solar cells. In this work， we utilized-alanine as a dual modifier to modify both transporting layers on PEDOT∶PSS（HTL） and PFN-Br（ETL） in the same device through a simple solution-processed technique， resulting in the synthesis of new interface layers. The modified PEDOT∶PSS（A-PEDOT∶PSS） exhibited superior properties compared to pristine PEDOT∶PSS， as evidenced by improvements in morphology， efficiency， and characteristic properties［37］. Positive influences were also observed for modified PFN-Br （A-PFN-Br）. Our findings indicate that the addition of-alanine resulted in an enhanced power conversion efficiency（PCE） of PM6∶Y6 solar cells， increasing from 14.99% to 15.78%. Furthermore， the addition of-alanine did not have a detrimental effect on light absorption， as shown by UV absorption and transmission data. FTIR analysis was conducted to confirm the modification， while surface morphology was analyzed using AFM. The current density-voltage（-） curve and dark current measurements also demonstrated an improvement. This study presents a unique modification that utilizes the same molecule in different materials to enhance device performance and stability， representing a novel approach that has not been previously explored in organic solar cells.

2 Experimental

2.1　Materials and Measurements

Poly［［4，8-bis［5-2-ethylhexyl］-4-fluoro-2-thienyl］benzo［1，2-b∶4，5-b∶4，5-b′］dithiophene-2，6-diyl）- 2，5 th-iophenediyl［5，7-bis（2-ethylhexyl）-4，8-dioxo-4H，8H-benzo［1，2-c∶4，5-c′］dithiophene-1，3-diyl］- 2，5-thiophene-diyl］）， PBDB-T-2F∶PM6， along with an acceptor material which was analyzed and used during the following work is Y6，（BTP-4F∶2，2′-（（2Z.2′Z）-（（12，13-bis（2-ethylhexyl）-3，9-diundecyl- 12，13-dihydro-［1，2，5］thiadiazol［3，4-e］thieno［2″，3″∶4′，5′］thieno［2′，3′∶4，5］pyrrolo［3，2-g］thieno［2′，3′∶4，5］thieno［3，2-b］indole-2，10-diyl）bis（methanylylidene））bis（5，6-difluoro-3-oxo-2，3-dihydro-1-indene-2，1-diylidene））dimalononitri-le））both were acquired from Solarmer Materials Inc. Chloroform（CF） and 1-chloronaphthalene（CN） were purchased from Sigma Aldrich and TCL， respectively. PEDOT∶PSS and PFN-Br were bought for buffer layer utilization， along with-alanine additive， which was purchased from Sigma Aldrich. Then， Isopropanol and acetone were obtained from Alfa Aesar Inc.

-characteristics of solar cells was measured on a Keithley 2400 source meter under AM 1.5G illumination（100 mW/cm2） provided by an Oriel solar simulator. The incident light intensity was adjusted with a silicon calibration photodiode（Peccell Technologies）. Single carrier devices were characterized by using a Keithley 2400 source in a dark environment. The Fourier transform infrared spectroscopy（FTIR） analysis was done by Spotlight 200i FT-IR microscopy system. The samples were prepared on CaF2substrates while spin-coating the solutions. The transmittance and absorbance spectra were attained by using a UV-Vis spectrometer（PerkinElmer Lamba 650/850/950 UV-Vis spectrometer）. The thin film samples were prepared on ITO substrates while spin-coating the solution of transporting layers（ETL/HTL） on it under the same conditions as for device fabrication. The contact angle analysis was done by DSA-100 static drop analyzer（KRÜSS Co.， Ltd.）. A water drop was dropped on the sample for the measurement. Atomic force microscope（AFM） height and phase images were taken by Bruker Multimode-8 microscope systemusing tapping mode. The samples were of thin films for the required conditions. The external quantum efficiency（EQE） spectra for solar cells were measured by using an Oriel Newport EQE measurement system（Model 66902） calibrated with a standard Si reference cell and equipped with a Newport Xenon lamp. Carrier mobility was measured using the space-charge-limit current（SCLC） method. The devices were fabricated under optimized conditions. The mobility was determined by fitting the dark current to the model of a single carrier SCLC， according to the equation：

= 90r2/83

where（A/cm2） is the current density，（V） is the applied voltage，（m） is the film thickness of the active layer，（cm2·V‒1·s‒1） is the charge carrier mobility，ris the relative dielectric constant of the transport medium， and0（C2·N‒1·m‒2） is the permittivity of free space. The carrier mobility was calculated from the slope of the0.5-curves.

2.2　Experimental Process

2.2.1Interface MaterialFor the interface modification， we used-alanine as an additive in both the electron and hole transporting layer（ETL and HTL） of organic solar cells， respectively. The pH of this additive is in the 6—7 dimension range.

2.2.2Interface Solution PreparationFor the preparation of the-alanine solution， its crystal powder was mixed with different fractions to form a new modified and optimized HTL and ETL to fabricate organic solar cell devices.

For HTL： We took an old classic HTL， PEDOT∶PSS， and dissolved 1 mg of-alanine in it.-alanine is a water-soluble compound so it swiftly gets dissolved into PEDOT∶PSS. The stirring time to form a new modified PEDOT∶PSS（in this work named A-PEDOT∶PSS） was 3 h at room temperature before use.

For ETL： We used PFN-Br as an ETL（at a concentration of 0.5 mg/mL in methanol） and for a modified ETL， we used 0.1 mg of-alanine into 0.4 mg of PFN-Br to one milliliter of methanol to form a modified PFN-Br solution（as A-PFN-Br）. The stirring time was overnight at room temperature in a nitrogen glovebox atmosphere.

2.2.3Bulk Heterojunction PreparationIn this study， we mainly used a non-fullerene acceptor（Y6）， and a polymer donor（PM6） to form a Bulk Heterojunction（BHJ） solution. The ratio of both donor and acceptor was 1∶1.2 at a total concentration of 16 mg/mL in chloroform（CF） solvent with an additive 1-chloronaphthalene（CN） of 0.5%（mass fraction）. The additive was dropped into the BHJ solution half an hour before coating on the interface HTL. The BHJ solution was stirred for 2 h at 40 ℃.

2.2.4Cleaning of SubstratesThe ITO substrates were scrubbed with detergent and then rinsed with distilled water， acetone， and IPA（isopropanol alcohol） followed by ultra-sonication for 15 min each. Then the substrates were sent for the UV-ozone treatment for 15 min.

2.2.5Device FabricationFor the device fabrication， the ITO substrates were taken out from the UVO3machine， and then the HTL solutions， PEDOT∶PSS and A-PEDOT∶PSS were spin-coated on ITO substrates at 4000 r/min to form a homogenous film and then baked at 150 ℃. Subsequently， the HTL-coated substrates were transferred to the N2-filled glovebox for the BHJ coating. The BHJ solution was spin-coated on HTL at 3000 r/min followed by annealing of 10 min at 110 ℃. Afterward， the ETL（PFN-Br and/or A-PFN-Br） was also spin-coated on BHJ at 3000 r/min. Finally， the metal deposition of Aluminium（Al） of 100 nm was done（shadow mask with an active area of 0.04 cm2） thermally at a vacuum pressure of 1×10‒4Pa.

3 Results and Discussion

The chemical structure of-alanine is depicted in Fig.1（A）， while Fig.1（B） illustrates PEDOT∶PSS， and Fig.1（C） depicts PFN-Br. Fig.1（D） demonstrates the dissolving technique employed in the fabrication process， and the resulting device architecture structure（conventional） is shown in Fig.1（E）. The compound-alanine is three carbons（C3） amino acid with amine as well as a carboxyl functional group on each side， respectively， both of these functional compounds are nucleophilic due to it has a strong polarity［38］. Although then the next question was which group will interact with which respective group of both PEDOT∶PSS and PFN-Br. To find out the answer to this， firstly we checked the solubility of-alanine in various solvents to have a simple clear thought about the miscibility of the compound. However， due to the general rule of “like dissolves like”［39］. We elected water（totally miscible just by shaking a small container）， alcohol（methanol and ethanol： soluble after stirring）， and DMF（required temperature and stirring）. Given that PEDOT∶PSS and PFN-Br are both soluble in polar solvents， with PEDOT∶PSS being soluble in aqueous solvents and PFN-Br being soluble in methanol， it is hypothesized that-alanine， being soluble in both solvents， would be suitable for modifying the interfacial layer materials of both PEDOT∶PSS and PFN-Br.

Fig.1　Chemical structures of β⁃alanine(A), PEDOT∶PSS(B) and PFN⁃Br(C), schematic illustration of mixing both transporting layers with β⁃alanine(D), schematic device structure representation of OSCs(E)

3.1　Device Performance

We explored the device performance of A-PEDOT∶PSS as HTL and A-PFN-Br as ETL in OSCs with the architecture of ITO/HTL/active layer/ETL/Al， where PM6 and Y6 are used as a donor and an acceptor in the active layer， respectively. Fig.1（E） represented the device structure. The devices which were used in this work are listed in Table 1. The-curves of the devices are summarized in Fig.2（A）. The control device（with normal PEDOT∶PSS and normal PFN-Br） obtained a PCE of 14.99% with an open-circuit voltage（OC） of 0.821 V， current density（SC） of 24.52 mA/cm2and fill factor（FF） of 74.43%. After analyzing the various concentrations for-alanine in PEDOT∶PSS and in PFN-Br， the optimized concentration was 1 mg/mL for A-PEDOT∶PSS， and volume ratio of-alanine/PFN-Br is 1∶4 for A-PFN-Br. The detailed preparation method is mentioned in the experimental section. The device with the A-PEDOT∶PSS showed a PCE of 15.56%， with aOC，SCand FF of 0.829 V， 25.35 mA/cm2and 73.96%， respectively. Next， the device with A-PFN-Br， disclosed a PCE of 15.65%， with aOCof 0.827 V，SCand FF of 25.91 mA/cm2and 73.39%， respectively. Lastly when we tried to use both transporting layers A-PEDOT∶PSS and A-PFN-Br at the same time in the same device， this dual-modified device revealed a PCE of 15.78% with aOCandSCof 0.828 V and 26 mA/cm2， respectively， along with a FF of 73.67%. Here， we noticed a decrease in the FF in the modified devices parameter， as we know FF decreases due to the presence of high series resistance. Reduction in depletion region causes further enhancement in the resistance that causes a reduction in FF. The FF of a solar cell is often the most difficult parameter to optimize because it is sensitive to a range of parasitic loss mechanisms， such as resistance losses. Shunt and series resistance can further reduce the FF of a practical device. In a simple cell model， these resistances are Ohmic elements. However， in practice both shunt and series resistance are not Ohmic in nature， therefore these non-Ohmic resistance greatly complicates the process of deconvoluting the various mechanisms responsible for a low FF. In the modified devices（single or dual） the FF is lower than that of the control devices due to the presence of higher resistances in the modified devices that resulted in the lower FF. The corresponding performance parameters are tabulated in Table 1.

Table 1　Photovoltaic parameters of the conventional architecture of OSCs based on PM6∶Y6 system with pristine PEDOT∶PSS, PFN∶Br and modified versions with β⁃alanine(A⁃PEDOT∶PSS and A⁃PFN⁃Br)a

.Substrate(ITO) and metal(Al) deposition were all the same for every device;. the average values/standard deviation for PCE are (14.88± 0.10) for control, (15.3±0.25) for A-PEDOT∶PSS, (15.50±0.12) for A-PFN-Br, and (15.51±0.18) for both. These calculations were based on 16 devices.

Fig.2　Current density versus voltage(J⁃V) curves of PM6∶Y6 active layer using different ETL and HTL modified layers(control, A⁃PEDOT∶PSS, A⁃PFN⁃Br and both)(A), dark J⁃V characteristics of various devices(B) and EQE spectra for PEDOT∶PSS and A⁃PEDOT∶PSS(C) and for PFN⁃Br and A⁃PFN⁃Br(D)

（A） The inset picture is a zoom-in on the curves.

The dark-graph is in Fig.2（B）. A dark current-voltage investigation is divided into three dominant regions. In region I（at low voltages） the-characteristics is primarily leakage currents determined bysh（shunt resistance）. Region II（intermediate voltages） accounts for recombination currents， and region III（at high voltages） accounts for series resistance［40，41］. When there was a dual modification（Both） device， dark-characteristics also spectated that the use of-alanine passivate the defects［30］of polymers of both the transpor-ting layers（ETL and HTL）， which is why the curve showed the lowest dark reverse［42，43］current among all. The dual-modified devices were better at blocking the activities［44］of electrons as well as holes in their respective interfaces and improving charge carrier selectivity. From the dark-graph， we also observed an increase in built-in voltage（bi）［45］for the condition of ‘Both’ to 1.05 V from the control device of 0.95 V. Thus， the increase inOCin the modified devices might be due to the increment of thebivalues. Then in the case of A-PEDOT∶PSS and A-PFN-Br， there are minor differences observed which might be due to the unmodified interface layer side， respectively. After that， EQE was tested for both the transporting layers（ETL and HTL） along with their modified versions. Fig.2（C） represents the PEDOT∶PSS and A-PEDOT∶PSS EQE， which showed a small increment in the 330—860 nm wavelength range for the modified layer. Fig.2（D） represents the EQE for the ETL devices of PFN-Br and A-PFN-Br. The increase in the EQE is due to the addition of-alanine that enhanced theSCof the modified devices for better charge transportation［46］.

3.2　Charge Carrier Mobility

Furthermore， we performed the SCLC characterization to count the charge carrier mobilities in the hole and electron-only devices. Fig.3（A）—（D） depicted the SCLC measurements for the interface layers. Fig.3（A） showed the PEDOT∶PSS SCLC charge mobility graph， the charge mobility was found to beh=2.18×10‒4cm2·V‒1·s‒1. The A-PEDOT∶PSS SCLC graph in Fig.3（C） showed that the charge mobilities increased to 2.48×10‒4cm2·V‒1·s‒1， this counts for an increase of 13.76% from the PEDOT∶PSS mobility. Next for PFN-Br， SCLC charge mobility ise=2.66×10‒4cm2·V‒1·s‒1［Fig.3（B）］， which also later in the A-PFN-Br elevated toe=2.98×10‒4cm2·V‒1·s‒1depicted in Fig.3（D）. For the electron mobilities， 12% increase has been shown for A-PFN-Br devices. Hence， it was concluded that-alanine addition aids in improved carrier mobilities. The respective device architecture structures are also illustrated in the SCLC graph of each layer（insets in Fig.3）.

Fig.3　SCLC carrier mobility graphs for hole transporting layers PEDOT∶PSS(A), electron transporting layer PFN⁃Br(B), modified HTL(A⁃PEDOT∶PSS)(C) and modified ETL(A⁃PFN⁃Br)(D)

Insets are device architecture structures.

3.3　Electrochemical Properties and Stability

Fig.4　FTIR analysis of PEDOT∶PSS with different percentages of β⁃alanine(A), FTIR of pristine PEDOT∶PSS(a) and PEDOT∶PSS with 2.0 mg of β⁃alanine(b)(B), UV⁃Vis absorption of PEDOT∶PSS and A⁃PEDOT∶PSS(C), UV⁃Vis absorption of PFN⁃Br and A⁃PFN⁃Br(D), transmittance of PEDOT∶PSS and A⁃PEDOT∶PSS(E) and transmittance of PFN⁃Br and A⁃PFN⁃Br(F), the normalized stability graph of different devices(G)

3.4　Morphology Characterization and Contact Angle Measurements

Fig.5　AFM images of PEDOT∶PSS height(A), phase(B) and A⁃PEDOT∶PSS height(C) and phase(D), PFN⁃Br height(E), phase(F), A⁃PFN⁃Br height(G), phase(H), the contact angle(water) of PEDOT∶PSS, A⁃PEDOT∶PSS(I) and PFN⁃Br and A⁃PFN⁃Br(J)

4 Conclusions

［1］ Zhou Z.， Xu S.， Song J.， Jin Y.， Yue Q.， Qian Y.， Liu F.， Zhang F.， Zhu X.，.，2018，（11）， 952—959

［2］ Gao W.， Qi F.， Peng Z.， Lin F. R.， Jiang K.， Zhong C.， Kaminsky W.， Guan Z.， Lee C. S.， Marks T. J.， Ade H.， Jen A. K. Y.，..，2022，（32）， 2202089

［3］ Armin A.， Li W.， Sandberg O. J.， Xiao Z.， Ding L.， Nelson J.， Neher D.， Vandewal K.， Shoaee S.， Wang T.， Ade H.， Heumüller T.， Brabec C.， Meredith P.，..，2021，， 2003570

［4］ Duan C.， Huang F.， Cao Y.，..，2015，（47）， 8081—8098

［5］ Wang J.， Zheng Z.， Zhang D.， Zhang J.， Zhou J.， Liu J.， Xie S.， Zhao Y.， Zhang Y.， Wei Z.， Hou J.， Tang Z.， Zhou H.，..，2019，（17）， 1806921

［6］ Du X.， Heumueller T.， Gruber W.， Almora O.， Classen A.， Qu J.， He F.， Unruh T.， Li N.， Brabec C. J.，..，2020，（16）， e1908305

［7］ Che X.， Li Y.， Qu Y.， Forrest S. R.，.，2018，（5）， 422—427

［8］ Yin Z.， Wei J.， Zheng Q.，..， 2016，（8）， 1500362

［9］ Li Y.， Ding J.， Liang C.， Zhang X.， Zhang J.， Jakob D. S.， Wang B.， Li X.， Zhang H.， Li L.， Yang Y.， Zhang G.， Zhang X.， Du W.， Liu X.， Zhang Y.， Zhang Y.， Xu X.， Qiu X.， Zhou H.，， 2021，（12）， 3154—3168

［10］ Chen M.， Wang J.， Yin F.， Du Z.， Belfiore L. A.， Tang J.，...，2021，（8）， 4505—4527

［11］ Kalkan S. B.， Najafidehaghani E.， Gan Z.， Apfelbeck F. A. C.， Hübner U.， George A.， Turchanin A.， Nickel B.，..，2021，（1）， 92

［12］ Kang H.， Hong S.， Lee J.， Lee K.，..，2012，（22）， 3005—3009

［13］ Liu M.， Xu Y.， Gao Z.， Zhang C.， Yu J.， Wang J.， Ma X.， Hu H.， Yin H.， Zhang F.， Man B.， Sun Q.，，2021，（25）， 11128—11137

［14］ Wu J.， Gao M.， Chai Y.， Liu P.， Zhang B.， Liu J.， Ye L.，.，2021，（4）， 100062

［15］ Kim H. I.， Bui T. T. T.， Kim G. W.， Kang G.， Shin W. S.， Park T.，..，2014，（18）， 15875—15880

［16］ Zhang X.， Zhang H.， Li Y.， Zafar S. U.， Yang S.， Chen J.， Zhou H.， Zhang Y.，...，2022，（44）， 2205398

［17］ Pei S.， Xiong X.， Zhong W.， Xue X.， Zhang M.， Hao T.， Zhang Y.， Liu F.， Zhu L.，..，2022，（30）， 34814—34821

［18］ Zheng Z.， Hu Q.， Zhang S.， Zhang D.， Wang J.， Xie S.， Wang R.， Qin Y.， Li W.， Hong L.， Liang N.， Liu F.， Zhang Y.， Wei Z.， Tang Z.， Russell T. P.， Hou J.， Zhou H.，..，2018，（34）， 1801801

［19］ Mengistie D. A.， Chen C. H.， Boopathi K. M.， Pranoto F. W.， Li L. J.， Chu C. W.，..，2015，， 94—100

［20］ Zhang L.， Yang K.， Chen R.， Zhou Y.， Chen S.， Zheng Y.， Li M.， Xu C.， Tang X.， Zang Z.， Sun K.，...， 2020，（1）， 1900648

［21］ Tang H.， Liu Z.， Hu Z.， Liang Y.， Huang F.， Cao Y.，..，2020，（6）， 802—809

［22］ Cassinelli M.， Park W. T.， Kim Y.， Kim J. H.， Noh Y. Y.， Caironi M.，..， 2021，3）， 033301

［23］ Hu L.， Song J.， Yin X.， Su Z.， Li Z.，，2020，（1）， 145

［24］ Li B.， Xiang Y.， Jayawardena K. D. G. I.， Luo D.， Wang Z.， Yang X.， Watts J. F.， Hinder S.， Sajjad M. T.， Webb T.， Luo H.， Marko I.， Li H.， Thomson S. A. J.， Zhu R.， Shao G.， Sweeney S. J.， Silva S. R. P.， Zhang W.，，2020，， 105249

［25］ Chen S.， Song L.， Tao Z.， Shao X.， Huang Y.， Cui Q.， Guo X.，..，2014，（12）， 3654—3659

［26］ Liu D.， Xu H.， Liu X.， Xie Z.， Yang B.， Ma Y.，..，2011，（1）， 174—180

［27］ Cameron J.， Skabara P. J.，.，2020，（7）， 1759—1772

［28］ Ionescu⁃Zanetti C.， Mechler A.， Carter S. A.， Lal R.，..，2004，（7）， 579

［29］ Liao Q.， Kang Q.， Yang Y.， An C.， Xu B.， Hou J.，..，2020，（7）， 1906557

［30］ Liu Y.， Cole M. D.， Jiang Y.， Kim P. Y.， Nordlund D.， Emrick T.， Russell T. P.，..，2018，（15）， 1705976

［31］ Li Y.，..，2016，（11）， 1430—1431

［32］ Jia J.， Fan B.， Xiao M.， Jia T.， Jin Y.， Li Y.， Huang F.， Cao Y.，，2018，（6）， 2195—2202

［33］ Hu Z.， Chen Z.， Zhang K.， Zheng N.，Xie R.， Liu X.， Yang X.， Huang F.， Cao Y.，，2017，（6）， 1700055

［34］ Guan L.， Yu L.， Wu L.， Zhang S.， Lin Y.， Jiao Y.， Zhang S.， Zhao F.， Ren Y.， Zhou X.， Liu Z.，，2021，， 138770

［35］ Ming Y.， Zhu Y.， Chen Y.， Jin B.， Duan C.， Liang Z.， Zhao L.， Wang S.， Dong B.， Li H.， Wu C.，..，2021，（48）， 57163—57170

［36］ Yuan H.， Zhang Z.， Guo T.， Yu L.， Deng Z.， Zhao R.， Zhang J.， Zhu Y.，..，2021，， 160140

［37］ Zheng Z.， Zhang S.， Zhang J.， Qin Y.， Li W.， Yu R.， Wei Z.， Hou J.，..，2016，（25）， 5133—5138

［38］ Sun P.， Liu Y.， Du S.， Yu B.， Wang Y.， Sun M.， Shi P.， Liu Y.， Gong J.，..，2017，， 522—531

［39］ Zou F.， Zhuang W.， Wu J.， Zhou J.， Liu Q.， Chen Y.， Xie J.， Zhu C.， Guo T.， Ying H.，...，2014，， 14—22

［40］ Servaites J. D.， Ratner M. A.， Marks T. J.，...，2011，（11）， 4410—4422

［41］ Servaites J. D.， Yeganeh S.， Marks T. J.， Ratner M. A.，...，2010，（1）， 97—104

［42］ Wu N.， Luo Q.， Bao Z.， Lin J.， Li Y. Q.， Ma C. Q.，...，2015，， 248—259

［43］ Wolf U.， Arkhipov V. I.， Bässler H.，.，1999，（11）， 7507—7513

［44］ Waldauf C.， Scharber M. C.， Schilinsky P.， Hauch J. D.， Brabec C. J.，...，2006，， 104503

［45］ Zhou H.， Zhang Y.， Seifter J.， Collins S. D.， Luo C.， Bazan G. C.， Nguyen T. Q.， Heeger A. J.，..，2013，（11）， 1646—1652

［46］ Lee B. R.， Lee S.， Park J. H.， Jung E. D.， Yu J. C.， Nam Y. S.， Heo J.， Kim J. Y.， Kim B. S.， Song M. H.，..，2015，（23）， 3553—3559

［47］ Konwar L. J.， Mäki⁃Arvela P.， Mikkola J. P.，.，2019，（22）， 11576—11630

［48］ Hara M.， Yoshida T.， Takagaki A.， Takata T.， Kondo J. N.， Hayashi S.， Domen K.，...，2004，（22）， 2955—2958

［49］ Li H.， Zhang C.， Ma Y.， Mai Y.， Xu Y.，..，2018，， 468—473

［50］ Aleshin A. N.， Williams S. R.， Heeger A. J.，..，1998，（2）， 173—177

［51］ Greczynski G.， Kugler T.， Salaneck W. R.，，1999，（1）， 129—135

［52］ Kemerink M.， Timpanaro S.， de Kok M. M.， Meulenkamp E. A.， Touwslager F. J.，...，2004，（49）， 18820—18825

［53］ Galatopoulos F.， Papadas I. T.， Ioakeimidis A.， Eleftheriou P.， Choulis S. A.，，2020，（10）， 1961

［54］ Müller C.， Hamedi M.， Karlsson R.， Jansson R.， Marcilla R.， Hedhammar M.， Inganäs O.，..，2011，（7）， 898—901

［55］ Liao C.， Zhang M.， Yao M. Y.， Hua T.， Li L.， Yan F.，..，2015，（46）， 7493—7527

［56］ Crispin X.， Jakobsson F. L. E.， Crispin A.， Grim P. C. M.， Andersson P.， Volodin A.， van Haesendonck C.， Van der Auweraer M.， Salaneck W. R.， Berggren M.，..，2006，（18）， 4354—4360

［57］ Xu H.， Yuan F.， Zhou D.， Liao X.， Chen L.， Chen Y.，...，2020，（23）， 11478—11492

［58］ Li W.， Zhang W.， Van Reenen S.， Sutton R. J.， Fan J.， Haghighirad A. A.， Johnston M. B.， Wang L.， Snaith H. J.，...，2016，（2）， 490—498

［59］ Dag I.， Lifshitz E.，...，1996，（21）， 8962—8972

［60］ Chang S. H.， Chiang C. H.， Kao F. S.， Tien C. L.， Wu C. G.，..，2014，（4）， 1—7

［61］ Hwang J.， Schwendeman I.， Ihas B. C.， Clark R. J.， Cornick M.， Nikolou M.， Argun A.， Reynolds J. R.， Tanner D. B.，.，2011，（19）， 195121

［62］ Akkerman H. B.， Naber R. C. G.， Jongbloed B.， van Hal P. A.， Blom P. W. M.， de Leeuw D. M.， de Boer B.，....，2007，（27）， 11161—11166

［63］ Yun D. J.， Jung J.， Sung Y. M.， Ra H.， Kim J. M.， Chung J.， Kim S. Y.， Kim Y. S.， Heo S.， Kim K. H.， Jeong Y. J.， Jang J.，...，2020，（11）， 2000620

［64］ Wang Q.， Chueh C. C.， Eslamian M.， Jen A. K. Y.，..，2016，（46）， 32068—32076

［65］ Hosseini E.， Ozhukil Kollath V.， Karan K.，...，2020，（12）， 3982—3990

［66］ Vorobyev A. Y.， Guo C.，.，2011，（Suppl 5）， A1031

［67］ Chao Y. C.， Chen C. Y.， Lin C. A.， Dai Y. A.， He J. H.，...，2010，（37）， 8134—8138

［68］ Li J.， Wang N.， Wang Y.， Liang Z.， Peng Y.， Yang C.， Bao X.， Xia Y.，.，2020，， 168—176

［69］ Shi Z.， Liu H.， Li J.， Wang F.， Bai Y.， Bian X.， Zhang B.， Alsaedi A.， Hayat T.， Tan Z. A.，...，2018，， 1—9

［70］ Bi S.， Leng X.， Li Y.， Zheng Z.， Zhang X.， Zhang Y.， Zhou H.，..， 2019，（45）， 1805708

［71］ Li Y.， Zhang Z.， Han X.， Li T.， Lin Y.，.，2022，（3）， 1087—1097

［72］ Cha H.， Wu J.， Wadsworth A.， Nagitta J.， Limbu S.， Pont S.， Li Z.， Searle J.， Wyatt M. F.， Baran D.， Kim J. S.， McCulloch I.， Durrant J. R.，..，2017，（33）， 1701156

［73］ Lee S. J.， Pil Kim H.， Mohd Yusoff A. R. B.， Jang J.，...，2014，， 238—243

［74］ Hermenau M.， Riede M.， Leo K.， Gevorgyan S. A.， Krebs F. C.， Norrman K.，...，2011，（5）， 1268—1277

［75］ Wang J.， Yu H.， Hou C.， Zhang J.，..，2020，（23）， 26543—26554

［76］ Mateker W. R.， McGehee M. D.，..，2017，（10）， 1603940

［77］ Lin X.， Wang Y.， Wu J.， Tang Z.， Lin W.， Nian L.，Yi G.，..，2021，（6）， 5905—5912

［78］ Cho A.， Kim S.， Kim S.， Cho W.， Park C.， Kim F. S.， Kim J. H.，....，2016，（15）， 1530—1536

［79］ Lee T. W.， Chung Y.，...，2008，（15）， 2246—2252

［80］ Zhou Y.， Fuentes⁃Hernandez C.， Shim J.， Meyer J.， Giordano A. J.， Li H.， Winget P.， Papadopoulos T.， Cheun H.， Kim J.， Fenoll M.， Dindar A.， Haske W.， Najafabadi E.， Khan T. M.， Sojoudi H.， Barlow S.， Graham S.， Brédas J. L.， Marder S. R.， Kahn A.， Kippelen B.，，2012，（6079）， 327—332

［81］ Mihailetchi V. D.， Blom P. W. M.， Hummelen J. C.， Rispens M. T.，...，2003，（10）， 6849—6854

［82］ López Valdivieso A.， Sánchez López A. A.， Song S.，...，2005，（3）， 154—164

［83］ Paredes Á.， Acuña S. M.， Toledo P. G.，，2019，（11）， 1177

［84］ Ouellette R. J.， Rawn J. D.，：，， Elsevier， Boston，2015， 169—182

［85］ Penczek S.， Kubisa P.， Allen G.， Bevington J. C.，⁃， Pergamon， Amsterdam，1989， 751—786

［86］ Savin K. A.，， Academic Press， Boston，2014， 1—53

［87］ Li J.， Huang X.， Yuan J.， Lu K.， Yue W.， Ma W.，..，2013，（9）， 2164—2171

［88］ Hau S. K.， Yip H. L.， Acton O.， Baek N. S.， Ma H.， Jen A. K. Y.，...，2008，（42）， 5113—5119

［89］ Chao L.， Niu T.， Gu H.， Yang Y.， Wei Q.， Xia Y.， Hui W.， Zuo S.， Zhu Z.， Pei C.， Zhang J.， Fang J.， Xing G.， Li H.， Huang X.， Gao X.， Ran C.， Song L.， Fu L.， Chen Y.， Huang W.，，2020，， 2616345

［90］ Yip H. L.， Hau S. K.， Baek N. S.， Ma H.， Jen A. K. Y.，..，2008，（12）， 2376—2382

-丙氨酸作为有机太阳能电池双重修饰添加剂的研究

Zafar Saud uz1，张伟超2，杨朔3，李世麟2，张莹玉1，张渊2，张弘1，周惠琼1

（1. 中国科学院大学, 中国科学院纳米系统与多级次制造重点实验室, 中国科学院纳米科学卓越中心, 国家纳米科学与技术中心, 北京 100190；2. 北京航空航天大学化学学院, 北京 100191； 3. 北京廷润膜技术开发股份有限公司, 北京 101100）

-丙氨酸；添加剂；界面改性；传输层；有机太阳能电池

O647.2

A

10.7503/cjcu20230185

2023-04-12

网络首发日期： 2023-05-31.

联系人简介：张弘, 男, 博士, 副研究员, 主要从事半透明柔性太阳能电池方面的研究. E-mail: zhanghong@nanoctr.cn

周惠琼, 女, 博士, 研究员, 主要从事有机太阳能电池和钙钛矿太阳能电池方面的研究. E-mail: zhouhq@nanoctr.cn

国家自然科学基金(批准号: 52273245)、中国科学院战略性先导科技专项(批准号: XDB36000000)和中国科学院-世界科学院校长博士奖学金计划项目资助.

Supported by the National Natural Science Foundation of China(No. 52273245), the Strategic Priority Research Program of Chinese Academy of Sciences(No. XDB36000000) and the Chinese Academy of Sciences-the World Academy of Sciences（CAS-TWAS） President’s Ph.D. Fellowship Program.

（Ed.： Y， K， S）