Pseudo‐Planar Heterojunction Organic Photovoltaics with Optimized Light Utilization for Printable Solar Windows

Abstract The existing conformation of the active layer is defective for employment of semitransparent organic solar cells (ST‐OSCs) in solar windows. Herein, scalable solar windows are successfully printed by introducing a pseudo‐planar heterojunction (PPHJ) structure. The PPHJ structure can effectively improve the average visible transmittance (AVT) value while boosting the power conversion efficiency (PCE) of semitransparent devices due to the reduced optical loss. The universality of the PPHJ structure in the preparation of ST‐OSCs is proved. Furthermore, an inset of a superhydrophobic patterned soft insertion layer (PSIL) in the encapsulated window improves the waterproof performance without losing transparency. Accordingly, the semitransparent devices based on the 2,2′‐((2Z,2′Z)‐((12,13‐bis(2‐ethylhexyl)‐3,9‐diundecyl‐12,13‐dihydro‐[1,2,5]thiadiazolo[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‐1H‐indene‐2,1‐diylidene))dimalononitrile (Y6) system afford a maximal efficiency of 14.62%, with a considerable AVT of 20.42%, and the resultant solar windows achieve a stabilized efficiency of 13.34% with excellent waterproof performance. Moreover, the PCE of the unilateral broken solar windows retains 70.6% of the initial efficiency after being placed under simulated rainfall conditions for 1200 h at room temperature.