Advancements in organic small molecule hole-transporting materials for perovskite solar cells: past and future

Abstract

This review article discusses the current designs and synthetic procedures for organic small molecules as hole-transporting materials (HTMs) with a focus on their structure–property correlation, conductivity, and photovoltaic performance, as...

Dibenzo heterocyclic-terminated spiro-type hole transporting materials for perovskite solar cells

“…8,9 Recently, lots of various types of HTMs have been designed and applied in PSCs. [10][11][12][13][14][15] Among them, spiro-type molecules are widely used in high-performance PSCs. 16 The spiro structures, such as common spirofluorene, possess a unique orthogonal molecular conformation due to the two molecular p-systems connected by the sp 3 -hybridized central carbon atom, which provide many advantages, including (1) rigidity due to the preferably acquired vertical arrangement and a highly sterically demanding structure, leading to high glass transition temperature (T g ); (2) a stable amorphous state below T g , leading to anisotropic charge transport properties; and (3) high solubility due to the extremely weak intermolecular p-p interaction.…”

Carbazolyl phenylacetone-based asymmetric hole transport material enables high-performance perovskite solar cells

“…[14][15][16][17] Various types of small molecule HTMs have been synthesized at this stage, such as spiro-type derivatives, D-A-D based linear molecules and star-shaped molecules, etc. 18 We note that the vast majority of these structures are symmetric, while HTMs based on asymmetric structures have rarely been reported. [19][20][21] According to previous studies, asymmetric molecular structures tend to exhibit good solubilities in organic solvents, excellent film-forming properties and high thermal stabilities.…”

Structural Engineering of FDT toward Promising Spiro-Typed Hole-Transporting Materials: Promoting the Hole Transport and Stabilizing the HOMO Levels

“…7−15 Recently, Wang et al have performed a series of studies on helicene-based HTMs for PSCs. 16−23 For instance, a racemic low-symmetric molecular semiconductor (O5H-OMeDPA) is synthesized initially with the oxa [5]helicene unit as the πlinker for semiconducting glassy film. 16 Meanwhile, the simplest double- [4]helicene, dibenzo[g,p] chrysene-based organic semiconductor (DBC-OMeDPA) has also been testified to be cost-effective in PSCs.…”