Ultraviolet‐Protective Transparent Photovoltaics Based on Lead‐Free Double Perovskites

Abstract

Perovskite solar cells have attracted great research interest as a promising candidate for silicon solar cells. Plenty of work has been reported to use perovskites to semitransparent windows and transparent photovoltaic (TPV) devices to obtain multifunctional systems. However, the narrow bandgap and sharp absorption edge of the typical perovskites prevent them from achieving the highest transparency to satisfy the requirements of aesthetic and integration, and the poor stability and toxic Pb compositions hinder their practical application. Herein, lead‐free halide double perovskites with a wide bandgap and indirect bandgap characteristics is introduced to fabricate long‐term stable transparent photovoltaic devices exhibiting high visible transmittance (73%) and considerable energy conversion efficiency (1.56%). Through further theoretical calculation and evaluation, a new strategy using indirect bandgap material on TPV devices is proposed to combine the enhancement of these two parameters. This approach will be a significant compliment to near‐infrared‐absorbing solar cells to selectively harvest light in the invisible region to obtain highly performing multi‐junction smart windows on buildings, vehicles and mobile electronics, providing a new reasonable idea to realize TPVs with high efficiency and transparency simultaneously.

Large Cation Engineering in Two-Dimensional Silver–Bismuth Bromide Double Perovskites

“…The valence band arises from Ag d 10 and Bi s 2 orbitals, resulting in a relatively deep valence band, heavy hole masses, and an indirect bandgap of ∼2 eV. − Despite the excellent stability, the indirect nature of the band gap, as well as its relatively wide value, strongly limits their applications in outdoor photovoltaics. On the other hand, interesting and useful applications have been identified for these species in other fields, such as photocatalysis, transparent, indoor and, in general, building-integrated photovoltaics, and radiation detection . The reduction toward two-dimensional (2D) monolayers, however, is an effective strategy to tune the band gap from indirect to direct, − thus opening new perspectives in the applications of DHPs in efficient optoelectronic devices. , …”

Alkali Metal Ion-Regulated Lead-free, All-Inorganic Double Perovskites for HTM-free, Carbon-Based Solar Cells

“…Upon systematical optimization, the film quality has been significantly improved and the defects are reduced, which in turn promotes the PCE up to 2.57%, a cutting-edge value for Pb-free, all-inorganic double PSCs and even the highest value for pure Cs 2 AgBiBr 6 PSCs (the corresponding device structures and performances of reported bismuth-based lead-free PSCs are summarized in Table S1). ,− ,,− …”

Methylammonium Bromide Assisted Crystallization for Enhanced Lead‐Free Double Perovskite Photovoltaic Performance

“…Compared to the opaque Cs 2 AgBiBr 6 solar cell (PCE = 2.53%), we observe slight performance loss and negligible hysteresis in the semitransparent device (PCE = 2.31%). Based on previous work, the calculation of AVT is express as: [ 36 ] where T (λ) is the wavelength‐dependent transmittance spectra, which was measured for whole device; D λ represents the relative spectral power distribution of standard illuminant D65, Δλ is the wavelength interval, and V (λ) represents the photopic response of the human eye. Our calculation was based on the spreadsheet calculator provided by Lunt's group, [ 37 ] through inputting the transmittance data, then obtaining the AVT of 31.81%.…”