Achieving High Open‐Circuit Voltage for p‐i‐n Perovskite Solar Cells Via Anode Contact Engineering

Abstract

With photocurrents in perovskite solar cells close to their practical limit, it is imperative to improve their open‐circuit voltage to go beyond a loss‐in‐potential less than 100 mV. However, state‐of‐the‐art p‐i‐n perovskite solar cells are reported with a Voc of around 1.1–1.5 V, limiting their efficiency improvement. Herein, the authors demonstrate that the Voc of p‐i‐n perovskite solar cells can be successfully improved via anode contact engineering. First of all, by introducing a partially oxidized nickel layer, the authors are able to remove the potential barrier for hole transport and enhance the crystallinity of the hole transporting layer, both of which are believed to contribute to the Voc and FF improvement. Furthermore, by separating the inorganic NiMgOx hole transporting layer from the perovskite absorbing layer with a poly(4‐vinylpyridine) (PVP) insulating layer, the interfacial recombination could be effectively suppressed, the Voc climbs to an impressive value of 1.15 V along with a power conversion efficiency of 19.3%. Finally, a substrate‐type perovskite solar cell is fabricated with an extremely high Voc of 1.18 V, representing a very low voltage deficit in the p‐i‐n perovskite solar cells. Our works provide an avenue for further reducing the loss‐in‐potential of perovskite solar cells.

Deepening the Valance Band Edges of NiOx Contacts by Alkaline Earth Metal Doping for Efficient Perovskite Photovoltaics with High Open‐Circuit Voltage

“…There are several kinds of device architectures (conventional mesoporous, conventional planar, inverted planar, HTLs‐ or ETLs‐free, etc) for PSCs, and the development of inorganic transport materials is crucial for stable and efficient devices . In recent years, several inorganic p‐type semiconductors, such as CuSCN, CuI, NiO x , and VO x , have been developed as HTLs in the inverted planar PSCs …”

Multifunctional device with an integration of light emitting, photo detective, and energy harvesting

“…The n‐type layer is zinc oxide (ZnO), while magnesium‐doped nickel oxide serves as the p‐type layer . In addition, an ultrathin poly(4‐vinylpyridine) (PVP) insulating layer is inserted between the p‐type NiMgO x and CsPbBr 3 to suppress exciton quenching at the interface . Figure B shows the energy band structure of the device.…”

“…7 In addition, an ultrathin poly(4-vinylpyridine) (PVP) insulating layer is inserted between the p-type NiMgO x and CsPbBr 3 to suppress exciton quenching at the interface. 4 Figure 1B shows the energy band structure of the device. Active layer of CsPbBr 3 and CdSe quantum dots (QDs) forms a type II heterojunction with an anisotropic staggered offset at the conduction band and the valence band.…”

“…However, endowing multiple functionality using a single‐device structure has always been challenging. This is because the processes of light‐to‐electricity and electricity‐to‐light are converse . For example, in an energy‐harvesting device, converting light into electricity requires efficient carrier separation and collection, while in a light‐emitting diode (LED), high efficiency relies on energetic carrier injection and effective radiative recombination.…”

“…This is because the processes of light-to-electricity and electricity-to-light are converse. 4,5 For example, in an energy-harvesting device, converting light into electricity requires efficient carrier separation and collection, while in a light-emitting diode (LED), high efficiency relies on energetic carrier injection and effective radiative recombination. Achieving efficient charge extraction and charge injection simultaneously using a traditional device structure is therefore impossible, as the device structure is presupposed to facilitate either the charge injection or the charge separation.…”