Interface modification layers for high-performance inverted organic photovoltaics

Recent progress in cathode interlayer materials for non‐fullerene organic solar cells

“…Besides, interface engineering through CIL plays a significant role in the improvement of OSCs devices. Recently, it has been demonstrated that interface engineering, primarily through inserting CIL between the electrode and photoactive layer could significantly enhance the performance of OSCs 89–91 . To achieve high efficiency, solution processible CIL should fulfill the following basic essential requirements: (1) To make ohmic contact, it should be able to make a proper energy level alignment with a photoactive layer for efficient electron transport and collection.…”

“…The appropriate work function of ZnO can effectively reduce the work function of the metal electrode or ITO to match with LUMO of fullerene and NFAs for electron extraction at the electrode 124 . The interfacial, optical, and electrical properties of ZnO could further be tuned through processing techniques by their variation in composition, defects, film thickness, film morphology, surface energy, and crystalline structure 90,125 . Previous studies clearly showed that the device performance change with adopting appropriate processing strategies, therefore controlling the property of ZnO is critical for efficient OSCs 126 .…”

“…124 The interfacial, optical, and electrical properties of ZnO could further be tuned through processing techniques by their variation in composition, defects, film thickness, film morphology, surface energy, and crystalline structure. 90,125 Previous studies clearly showed that the device performance change with adopting appropriate processing strategies, therefore controlling the property of ZnO is critical for efficient OSCs. 126 Several approaches have been employed to improve the properties of ZnO for efficient OSCs.…”

“…Recently, it has been demonstrated that interface engineering, primarily through inserting CIL between the electrode and photoactive layer could significantly enhance the performance of OSCs. [89][90][91] To achieve high efficiency, solution processible CIL should fulfill the following basic essential requirements: (1) To make ohmic contact, it should be able to make a proper energy level alignment with a photoactive layer for efficient electron transport and collection. 5) It should have good film-forming properties and the ability to be processed from solution at low cost and lower temperature.…”

Inverted organic photovoltaics with a solution-processed ZnO/MgO electron transport bilayer

“…Contradictory reports can be found in the literature regarding how the surface roughness of the ETL affects the PCE of OPVs. Some reports show enhanced photovoltaic performance upon an increase in rms roughness 20,43 while others support that an increase in performance is a result of a lower surface roughness 18,19,25,27,41 . Both cases are equally valid but need a further distinction.…”