Charge-Transporting-Layer-Free, Vacuum-Free, All-Inorganic CsPbIBr2 Perovskite Solar Cells Via Dipoles-Adjusted Interface

Abstract

<jats:p>The inorganic perovskite has a better stability than the hybrid halide perovskite, and at the same time it has the potential to achieve an excellent photoelectric performance as the organic-inorganic hybrid halide perovskite. Thus, the pursuit of a low-cost and high-performance inorganic perovskite solar cell (PSC) is becoming the research hot point in the research field of perovskite devices. In setting out to build vacuum-free and carbon-based all-inorganic PSCs with the traits of simple fabrication and low cost, we propose the ones with a simplified vertical structure of FTO/CsPbIBr2/carbon upon interfacial modification with PEI species. In this structure, both the electron-transporting-layer and hole-transporting-layer are abandoned, and the noble metal is also replaced by the carbon paste. At the same time, FTO is modified by PEI, which brings dipoles to decrease the work function of FTO. Through our measurements, the carrier recombination has been partially suppressed, and the performance of champion PSCs has far exceeded the control devices without PEI modification, which yields a power conversion efficiency of 4.9% with an open circuit voltage of 0.9 V and a fill factor of 50.4%. Our work contributes significantly to give an available method to explore charge-transporting-layer-free, low-cost, and high-performance PSCs.</jats:p>

Enhancing the stability and crystallinity of CsPbIBr2 through antisolvent engineering

“…The champion cell, where TiO 2 was used as an ETL, gave a PCE of 13.7%, which is higher than the record experimental value of 11.53% [42]. To date, much focus has been made on HTL-free CsPbIBr2-based devices [15,21,31,34], and our findings suggest that many of the experimentally tested devices could be significantly enhanced by the addition of an appropriate HTL.…”

“…Based on these papers, IPA appears to be an antisolvent that lends itself well to approaches where only DMSO is used as a solvent, however, as soon as DMF is added to the solvent, other antisolvents perform better. Since initial literature reviews of researchers working on CsPbIBr 2 may not include sister materials, and the vast majority of CsPbIBr 2 films are made with DMSO [31,34,35,42], our findings should be taken into account by other researchers, since they may not be aware that there is an alternative antisolvent quenching method available to the one presented by Zhang et al…”

“…[21,33]. Moreover, CsPbIBr 2 films have been deposited via: one-step spin coating [30,31,34], a gas-assisted method [35], a spray-assisted method [25], a two-step spin coating method [21] and by dual-source thermal evaporation [15]. While antisolvent quenching has been shown to significantly improve a range of perovskite materials [36][37][38][39], we were surprised to note a lack of literature reporting its use with CsPbIBr 2 , with Liu et al reporting its use in a vapour-assisted deposition [40] and only Zhang et al reporting the use of antisolvents with a one-step spin coating procedure.…”

Low‐temperature crystallization and growth of CsPbIBr 2 films through PbX 2 ‐DMSO adduct towards stable and efficient carbon‐based all‐inorganic perovskite solar cells

“…and hole selective layers (HSLs) are used in high-efficiency PSCs, but they make the device as unstable one like organic HSLs (spiro-OMeTAD, PEDOT: PSS, etc.). 21,22 Hence, researchers are drawn to HSL-free carbon-electrodebased PSCs (C-PSCs), which are advantageous due to carbon's low cost, simple deposition process, chemical stability, hydrophobicity and high hole extraction capability. 22 Carbon layer in C-PSCs mainly protects the perovskite layer from moisture and increases the stability of device under ambient conditions.…”

Special Issue: Perovskite Nanostructures: From Material Design to Applications

“…The performance of the device based on the all-inorganic perovskite and titanium dioxide presented power conversion efficiency up to 6.39%. Finally, in the Special Issue, a simplified vertical structure of FTO–CsPbIBr 2 –carbon upon interfacial modification with polyethyleneimine species is suggested, yielding a power conversion efficiency of 4.9% with an open circuit voltage of 0.9 V and a fill factor of 50.4% [ 9 ].…”