Antimony Selenide Thin Film Solar Cells with an Electron Transport Layer of Alq3*Supported by the High Level Talents Project of Hainan Basic and Applied Research Program (Natural Science) (Grant No. 2019RC118), and the Open Fund of the State Key Laboratory of Molecular Reaction Dynamics in DICP (Grant No. SKLMRDK202005).

Abstract

We fabricated Sb2Se3 thin film solar cells using tris(8-hydroxy-quinolinato) aluminum (Alq3) as an electron transport layer by vacuum thermal evaporation. Another small organic molecule of N,N’-bis(naphthalen-1-yl)-N,N’-bis(phenyl)benzidine (NPB) was used as a hole transport layer. We took ITO/NPB/Sb2Se3/Alq3/Al as the device architecture. An open circuit voltage (Voc) of 0.37 V, a short circuit current density (Jsc) of 21.2 mA/cm2, and a power conversion efficiency (PCE) of 3.79% were obtained on an optimized device. A maximum external quantum efficiency of 73% was achieved at 600 nm. The Jsc, Voc, and PCE were dramatically enhanced after introducing an electron transport layer of Alq3. The results suggest that the interface state density at Sb2Se3/Al interface is decreased by inserting an Alq3 layer, and the charge recombination loss in the device is suppressed. This work provides a new electron transport material for Sb2Se3 thin film solar cells.