Enhanced inverted perovskite solar cells via indium doped nickel oxide as hole transport layer
Martín González-Hernández, Sergio E. Reyes, Eider A. Erazo, Pablo Ortiz, Marı́a T. Cortés
Abstract
• Indium-doped NiOx layers as HTL in inverted perovskite solar cells. • The champion cell was based on NiOxIn-0.5% with a PCE of 20.06%. • Favorable microstructural changes in perovskite layer induced by NiOxIn. • Enhanced charge transport properties of NiOx induced by doping with In. Nickel oxides have been widely used as hole transport layer (HTL) in inverted perovskite solar cells (IPSCs), although the inherent electric limitations of the pristine NiOx material have driven research on its modifications. In this work, the electrochemical deposition (ECD) of indium-doped NiOx layers (NiOxIn) on indium tin oxide (ITO) substrates was investigated for the first time and their properties as HTL in IPSCs were evaluated. It was found that an In:Ni ratio of 0.5 % in the synthesis solution (NiOxIn0.5 %) produced the champion device with power conversion efficiency (PCE) of 20.06 %, Voc of 1.11 V and FF of 78.19 %, while the undoped NiOx IPSC showed a champion PCE of 17.92 %. The stability of the IPSCs was evaluated by tracking the maximum power point during 3000 s and through monitoring photovoltaic parameters for 46 days. Results indicate high stability for both the doped and undoped electrochemical NiOx based devices. Indium doping of NiOx was found to decrease its charge transfer resistance and induce structural changes in the perovskite (PVK) layer, such as increasing its grain size and crystallinity. These effects lead to improved compatibility of the HTL/PVK interface, resulting in low series resistance, better holes extraction and ultimately improved cell performance.