Hydrazone-based hole transporting material prepared via condensation chemistry as alternative for cross-coupling chemistry for perovskite solar cells

Abstract

We introduce a new class of HTMs that are based on a hydrazone-backbone to the field of perovskite solar cells. The simple synthesis allows these materials to be produced at a low-cost.

New Thiophene Imines Acting as Hole Transporting Materials in Photovoltaic Devices

“…An example of imine examination is when tris-4-iminophenyl-ethyl-thiophene is used as a sensitizer in a DSSC and the device shows an open circuit voltage and a short circuit current of about 0.62 V and 0.35 mA, respectively . As mentioned earlier, imines were also applied as hole transporting materials (HTMs) in PSCs. − Petrus et al , reported a series of imines with various cores (EDOT, thiophene, furan, TPA, and benzene) end-capped with the TPA unit employed in PSCs. The fabricated PSC exhibited a PCE in the broad range of 0.2–14.4% being the highest for imines consisting of EDOT end-capped with TPA.…”

“…Therefore, new stable, processable organic compounds that are able to meet the continually increasing demands are being sought. − Among the various π-conjugated compounds, azomethines have attracted broad research interest as components in optoelectronic devices. − Imines are synthesized under mild reaction conditions, where only water is formed as a byproduct (the reaction is not harmful to the environment), and do not require a complicated purification process and metal catalysts. − , The possibility of modification of the azomethine structure through the appropriate selection of amines and carbonyl compounds allows for the preparation of new compounds with the desired properties. Considering the chemical structure of the investigated imines for organic electronics, special attention is paid to heterocyclic azomethines with a thiophene unit. − Compounds with a thiophene structure exhibit many desirable properties in optoelectronics, such as low oxidation potentials, low band-gap energy, good electrical conductivity, and chemical and thermal stability. ,− ,, Apart from the various fields of imine applications, they are also investigated as materials for photovoltaic (PV) cells. − Nowadays, they are examined in bulk heterojunctions (BHJs), − dye-sensitized solar cells (DSSCs), and perovskite solar cells (PSCs). − Bogdanow...…”

New Generation Hole Transporting Materials for Perovskite Solar Cells: Amide‐Based Small‐Molecules with Nonconjugated Backbones

“…In contrast, our recently introduced approach using condensation chemistry has proven its value as a low‐cost and easily scalable chemistry to prepare organic HTMs for perovskite solar cells . More importantly, no expensive metal catalysts are required when using this chemistry, the synthesis can be done at ambient conditions and since water is the only side‐product, product purification is very straightforward .…”

“…More importantly, no expensive metal catalysts are required when using this chemistry, the synthesis can be done at ambient conditions and since water is the only side‐product, product purification is very straightforward . Azomethine‐, enamine‐, and hydrazone‐based organic molecules have been reported as HTMs, although none of these materials have been able to outperform state‐of‐the‐art materials …”

Beyond efficiency: phenothiazine, a new commercially viable substituent for hole transport materials in perovskite solar cells

“…To assess the material cost of the HTM we have used a procedure reported by Osedach et al for materials in organic photovoltaics and followed the work by Petrus et al which introduced it to the field of HTMs for perovskites. 29,32,33 We have simplified the cost estimation by omitting the costs of workup and purification since on the small scale chlorinated solvents and column chromatography increase the cost of the final material significantly but these steps would be substituted by the appropriate solvent choice and the recrystallization procedure on the process development stage. The estimated cost of the materials for the central 1,3,5-tris(2-bromophenyl)benzene core is 1.64 $ g À1 ; for the final HTMs we found 12.98 $ g À1 and 3.09 $ g À1 for TPB(2-MeOTAD) and TPB(2-TPTZ), respectively (see the ESI, † from more details).…”