Efficient planar heterojunction perovskite solar cells by vapour deposition

Abstract

Many different photovoltaic technologies are being developed for large-scale solar energy conversion. The wafer-based first-generation photovoltaic devices have been followed by thin-film solid semiconductor absorber layers sandwiched between two charge-selective contacts and nanostructured (or mesostructured) solar cells that rely on a distributed heterojunction to generate charge and to transport positive and negative charges in spatially separated phases. Although many materials have been used in nanostructured devices, the goal of attaining high-efficiency thin-film solar cells in such a way has yet to be achieved. Organometal halide perovskites have recently emerged as a promising material for high-efficiency nanostructured devices. Here we show that nanostructuring is not necessary to achieve high efficiencies with this material: a simple planar heterojunction solar cell incorporating vapour-deposited perovskite as the absorbing layer can have solar-to-electrical power conversion efficiencies of over 15 per cent (as measured under simulated full sunlight). This demonstrates that perovskite absorbers can function at the highest efficiencies in simplified device architectures, without the need for complex nanostructures.

Formation and Diffusion of Metal Impurities in Perovskite Solar Cell Material CH3NH3PbI3: Implications on Solar Cell Degradation and Choice of Electrode

“…The Fermi level of MAPbI 3 is not expected to be close to the VBM or the CBM because MAPbI 3 typically has a low free carrier concentration 78, 79. As shown in Figure 1 , the calculated formation energies of the interstitial metal impurities are mostly low when the Fermi level is in the midgap region, except for the cases of W i and Mo i exhibiting the formation energies above 1 eV.…”

Lead‐Free Hybrid Perovskite Absorbers for Viable Application: Can We Eat the Cake and Have It too?

“…Therefore, developing novel preparation methods to achieve high‐quality tin perovskite film is of great importance to boost both efficiency and stability of Sn‐based PSCs. In lead‐based perovskites, the methods for morphology engineering include addition of additives,157, 158, 159 solvent engineering,160, 161 vacuum engineering,162, 163 thermal annealing,164 self‐healing,165 vapor deposition,166 and so on. Herein, the reported methods used for preparing high‐quality tin perovskite layers are introduced.…”

“…Generally, vapor deposition process is known to provide higher controllability over perovskite films fabrication in terms of higher homogeneity, smoothness, and surface coverage than solution‐processed films 166, 172. Moreover, the vacuum condition adopted in vapor deposition process is especially beneficial to air‐sensitive tin perovskite.…”

Recent Progress on the Long‐Term Stability of Perovskite Solar Cells

“…Furthermore, low‐cost, environment‐friendly new solar cells become the focus of widespread concern. Among all the PV technologies, the perovskite solar cells (PVSCs) have attracted much attention3, 4, 5, 6, 7, 8, 9, 10, 11 and considered to be a major discovery in the field of photovoltaics 12. The current highest certified power conversion efficiency (PCE) of PVSCs has reached 22.1% 13…”