“…Most studies on RNO thus far have focused on the origin of the metal–insulator transition. ,− Ramanathan et al have explored the multifunctional applications of RNO, especially SmNiO 3 (SNO), in synaptic transistors, solid fuel cells, and electric-field sensors in salt water . However, up until now, little is known about potential applications of RNO in optoelectric devices, − although the bandgap of RNO can be tuned by changing the A-site cation. We have previously reported that the bandgap of NdNiO 3 (NNO) can be continuously tuned by changing its oxygen content, leading to possible applications in photovoltaic devices. , It is thus of great scientific and technological interest to examine the effect of changing the A-site rare-earth element on photovoltaic response.…”