Hole transport layers based on metal Schiff base complexes in perovskite solar cells

Non-peripherally octaalkyl-substituted nickel phthalocyanines used as non-dopant hole transport materials in perovskite solar cells*

“…[1,31] thin film crystallinity as well as higher order of molecular arrangements within the thin film, which is more beneficial for hole extraction and transport, and thus leads to higher J SC and FF found for the NiPr 2 Pc-based PSC. [12] Atomic force microscopy (AFM) technologies were employed to study the morphologies of the HTLs, as illustrated in Fig. 7.…”

“…Further, due to the inherently low conductivity of the pristine spiro-OMeTAD, hydrophilic additives such as lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), 4-tertbutyl pyridine (TBP), and so on, are usually necessary in order to improve the HTL conductivity, which induces poor device stability in air. [9,11,12] As one class of small-molecule HTMs, organometallic compounds that contain a delocalized 18 π-electron conjugated system with a metal ion located at the central cavity, have also attracted considerable research attentions and efforts in recent years due to their excellent hole extraction and transport ability when employed as HTMs in PSCs. [8,9,[11][12][13][14] So far, metal phthalocyanines (MPcs) are one of the most widely studied organometallic HTMs in PSCs.…”

“…[9,11,12] As one class of small-molecule HTMs, organometallic compounds that contain a delocalized 18 π-electron conjugated system with a metal ion located at the central cavity, have also attracted considerable research attentions and efforts in recent years due to their excellent hole extraction and transport ability when employed as HTMs in PSCs. [8,9,[11][12][13][14] So far, metal phthalocyanines (MPcs) are one of the most widely studied organometallic HTMs in PSCs. [15] This class of HTMs could be an ideal alternative to the expensive spiro-OMeTAD due to simple synthesis and easy purification, [8,9,16] as well as superior semiconducting nature originating from the interaction between organic ligand and central metal.…”

Recent advances in semitransparent perovskite solar cells

“…176,177 A good number of hole transport materials were developed to be an alternative of hole transport layer in order to enhance stability. 178,179 Solidstate hole transporters are divided into three categories: polymeric, inorganic, and small organic molecule holetransporting materials (HTM). 180 The inorganic HTMs are used in the PSCs due to their excellent properties such as high hole mobility and low cost.…”

“…By doping some organic cations such as Rb and Cs is also a good testing tool to improve thermal stability 176,177 . A good number of hole transport materials were developed to be an alternative of hole transport layer in order to enhance stability 178,179 . Solid‐state hole transporters are divided into three categories: polymeric, inorganic, and small organic molecule hole‐transporting materials (HTM) 180 .…”