A Methoxydiphenylamine‐Substituted Carbazole Twin Derivative: An Efficient Hole‐Transporting Material for Perovskite Solar Cells

Abstract

The small-molecule-based hole-transporting material methoxydiphenylamine-substituted carbazole was synthesized and incorporated into a CH3NH3PbI3 perovskite solar cell, which displayed a power conversion efficiency of 16.91%, the second highest conversion efficiency after that of Spiro-OMeTAD. The investigated hole-transporting material was synthesized in two steps from commercially available and relatively inexpensive starting reagents. Various electro-optical measurements (UV/Vis, IV, thin-film conductivity, hole mobility, DSC, TGA, ionization potential) have been carried out to characterize the new hole-transporting material.

High‐Efficiency Perovskite Solar Cells Using Molecularly Engineered, Thiophene‐Rich, Hole‐Transporting Materials: Influence of Alkyl Chain Length on Power Conversion Efficiency

“…[18][19][20][21][22][23][24][25][26] An alternative chemical approach for designing high efficient HTMs is based on polycyclic aromatics as a central core, such as pentacene, [27] triazatruxene, [28] thiolated nanographene [29] or benzotrithiophene, [30] endowed with arylamines derivatives. These -conjugated structures show excellent holetransporting properties due to the stacking of the planar structure through intramolecular - interactions, which lead to excellent power conversion efficiencies.…”

“…Remarkable conductivity was observed for ATT-OMe (5.8 × 10 -4 S cm -1 ), which is even higher than that previously measured for spiro-OMeTAD (8.7 × 10 -5 S cm -1 ). [25] Upon increasing the length of the alkyl chains the conductivity decreases gradually, and for ATT-ODec the conductivity value was found to be two orders of magnitude lower than for ATT-OMe. These findings are in good agreement with the device performance.…”

π-Conjugated Materials as the Hole-Transporting Layer in Perovskite Solar Cells

“…Another serious candidate reported in the recent literature for the replacement of Spiro-OMeTAD is the methoxydiphenylamine-substituted carbazole twin derivative (referred to as V886) [26]. These small molecules are easily synthetized from a reaction of 1,2-bis(bromomethyl)benzene with 3,6-dibromocarbazole, followed by a palladium-catalyzed C-N cross coupling reaction with 4,4 1 -dimethoxydiphenylamine.…”

Low‐Cost Carbazole‐Based Hole‐Transport Material for Highly Efficient Perovskite Solar Cells

“…[15][16][17][18] Liu et al reporteds piro[fluorene-9,9'-xanthene]-basedH TMs for PSCs, in which not only ah igh PCE but also improved stabilityw ere achieved. [23][24][25][26][27][28][29][30][31][32] In the molecular structures of many HTMs, ac arbazole moiety together with some atypical hole-transport groupsf orm the core of the molecule and a phenylamine structure are found on the outsideo ft he molecule core. However,t hese materials and Spiro-OMeTAD all contain fluoride groups, which are responsible for al arge proportion of the final cost of the ultimate product.…”

“…[19] Xu et al [20] and Bi et al [21] achieved high PCEs of over 19 % using similarly structured small-molecule materials (X59 and X60). [23,24,[26][27][28][29] These atypical hole-transportg roups( e.g., benzene and biphenyl) can transport both holes and electrons, which mayi mpair the hole mobility of theseHTMs. The replacement of fluorine with al ess expensive substitute seems to be an effective way to cut the cost of the HTMs.…”