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One of the most crucial considerations for practical applications of organic photovoltaics (OPV) is the stability under sunlight irradiation. It is necessary to translate the small device stability to the module level. Herein, the photostability of the OPV module with three cells connected in series with a total effective area of 10.8 cm2 is presented. The stability of the OPV module is studied under continuous irradiation by a UV light‐emitting diode (LED) with integrated UV intensity the same as AM1.5 solar irradiations. As a result, the OPV module achieves good stability under UV light with a half‐lifetime of about 1300 h without a UV filter. The lifetime is similar to the small device with the same materials. The series resistance and the encapsulation must be optimized simultaneously. The suitable metal of the external electrode greatly improves the OPV module's performance. In addition, the UV stability of the normal structure is shown to be better than the inverted structure because of the photoinstability of the ZnO layer. Moreover, the UV stability of semitransparent OPV modules is shown to be‐ similar to the opaque ones. [ABSTRACT FROM AUTHOR]

A polymer solar cell involving a nonfullerene acceptor is made by blade coating. In the ternary bulk‐heterojunction layer, the donor is poly[(2,6‐(4,8‐bis(5‐(2‐ethylhexyl)thiophen‐2‐yl)benzo[1,2‐b:4,5‐b']dithiophene))‐co‐(1,3‐di(5‐thiophene‐2‐yl)‐ 5,7‐bis(2‐ethylhexyl)benzo[1,2‐c:4,5‐c']dithiophene‐4,8‐dione)] (PBDB‐T) and the acceptor is a mixture of 3,9‐bis(2‐methylene‐(3‐(1,1‐dicyanomethylene)‐indanone))‐5,5,11,11‐tetrakis(4‐hexylphenyl)‐dithieno[2,3‐d:2',3'‐d']‐s‐indaceno[1,2‐b:5,6‐b']dithiophene) (ITIC) and [6,6]‐phenyl C71‐butyric acid methyl ester (PC71BM). The device structure is an indium tin oxide (ITO)‐coated glass substrate/PEDOT:PSS/ternary active layer/interfacial layer/Al. For a small active area of 0.04 cm2, the best power conversion efficiency is 9.8% with the LiF interfacial layer. For a large active area of 216 cm2, the best efficiency is 7.7% with the ZrOx interfacial layer. After annealing at 85 °C for 30 days, the large‐area device keeps 75% of the initial efficiency. The efficiency of 4.9% is achieved for a large‐area semi‐transparent device. [ABSTRACT FROM AUTHOR]