Fabrication of planar heterojunction CsPbBr₂I perovskite solar cells using ZnO as an electron transport layer and improved solar energy conversion efficiency

Abstract

Inorganic cesium lead bromoiodide based planar perovskite solar cells with ZnO electron transport layers are deposited using one step spin coating.

Band Alignment Engineering Towards High Efficiency Carbon‐Based Inorganic Planar CsPbIBr2 Perovskite Solar Cells

“…[22,23] Moreover,t he extra high-density grain boundaries or long-chain surfactants used to improve processing of the materials lead to inferiorP CEs. [6,14,15,[24][25][26][27][28][29][30][31][32][33] An impressive PCE of 9.16 %w as achieved for carbon-based all-inorganic PSCs with pure CsPbIBr 2 in our previousw ork. [6,14,15,[24][25][26][27][28][29][30][31][32][33] An impressive PCE of 9.16 %w as achieved for carbon-based all-inorganic PSCs with pure CsPbIBr 2 in our previousw ork.…”

“…[22] On the other hand, CsPbIBr 2 has an arrower band gap ( % 2.05 eV) than CsPbBr 3 and better stabilityt han both CsPbI 3 and CsPbI 2 Br. [6,14,15,[24][25][26][27][28][29][30][31][32][33] An impressive PCE of 9.16 %w as achieved for carbon-based all-inorganic PSCs with pure CsPbIBr 2 in our previousw ork. [24] Doping CsPbIBr 2 with Mn 2 + or Sn 2 + was shown to further boost the cell efficiency to over 11 %.…”

“…We varied the spin-coating speed of CsBr solution from 5000, 4000, 3000, to 2000 rpm during the preparation of TiO 2 /CsBr ETLs. [6,14,15,21,[24][25][26][27][28][29][30][31][32][33] Under forwards can, the cells with TiO 2 and TiO 2 /CsBr ETLs yield PCEs of 6.44 %and 8.11%,respectively.T hese results indicatet hat J-V hysteresis exists, which seems to be ac ommon phenomenon for CsPbIBr 2 solar cells. Therefore, this condition is adopted to prepare TiO 2 /CsBr ETLs.…”

“…To the best of our knowledge,s uch PCE is the highest value achieved for pure CsPbIBr 2 -based PSCs reported so far,w ith or without HTLs, as listed in Table 1. [6,14,15,21,[24][25][26][27][28][29][30][31][32][33] Under forwards can, the cells with TiO 2 and TiO 2 /CsBr ETLs yield PCEs of 6.44 %and 8.11%,respectively.T hese results indicatet hat J-V hysteresis exists, which seems to be ac ommon phenomenon for CsPbIBr 2 solar cells. [6,29] The photocurrent densities of the cells at their respective maximum power points were tested as af unctiono ft ime, as given in Figure 4c.T he stabilized photocurrent densities of 9.32 and9 .82 mA cm À2 are obtained for the cells with TiO 2 and TiO 2 /CsBr ETLs, respectively,w hich correspond to the PCEs of 8.20 %a nd 9.82 %.…”

Device Physics of the Carrier Transporting Layer in Planar Perovskite Solar Cells

“…Regarding the inorganic semiconductor materials, metal oxides possess superior stability and tunable optical and electrical properties compared with the organic semiconductor materials. The various metal oxides such as titanium dioxide (TiO 2 ), zinc oxide (ZnO), and tin oxide (SnO 2 ) are commonly used as the electron transport layer (ETL), while nickel oxide (NiO x ), copper oxide (Cu 2 O), copper (I) thiocyanate (CuSCN), copper gallium oxide (CuGaO 2 ), and nickel cobalt oxide (NiCoO x ) serve as the hole transport layer (HTL) in the PVSCs . Meanwhile, several theoretical studies based on different approaches to the device models have also been reported, focusing on the underlying physics of the efficiency loss, hysteresis phenomena, etc., which are substantially affected by the carrier transport layer (CTL) properties.…”