Contact passivation for perovskite optoelectronics

A perovskite-based optoelectronic device, comprising:

• a) an optically transparent electrode;
• b) a semiconductor electron transport layer on said optically transparent electrode;
• c) a light-absorbing perovskite layer formed on said semiconductor electron transport layer;
• d) the electron transport layer having a surface located at an interface or junction between the semiconductor electron transport layer and the light-absorbing perovskite layer at least partially capped with a ligand Z, wherein said ligand Z is selected to passivate surface states at said interface or junction between the semiconductor electron transport layer and the light-absorbing perovskite layer;
• and
• e) a hole transport layer on said light-absorbing perovskite layer, and including an electrode layer located on said hole transport layer.