Quinoidal 2,2′,6,6′‐Tetraphenyl‐Dipyranylidene as a Dopant‐Free Hole‐Transport Material for Stable and Cost‐Effective Perovskite Solar Cells

Abstract

We report on the use of 2,2′,6,6′‐tetraphenyldipyranylidene (DIPO‐Ph4), a large quinoidal planar π‐conjugated heterocycle, as a simple, easy‐to‐synthetize, and efficient dopant‐free hole‐transport material in perovskite solar cells (PSCs). PSCs using pristine DIPO‐Ph4 show photon conversion efficiencies up to 10.1 %, which is higher than a PSC utilizing dopant‐free spiro‐OMeTAD (5.1 %). DIPO‐Ph4‐based PSCs exhibit a short‐circuit current density of 19.52 mA cm−2 and an open‐circuit voltage of 0.933 V, values that are superior to dopant‐free spiro‐OMeTAD and comparable to doped spiro‐OMeTAD. These better performances find their origin in a higher HOMO level (−4.74 eV) and a much higher hole mobility (2×10−2 cm2 V−1 s−1). Finally, PSCs based on DIPO‐Ph4 possess a superior stability compared to doped‐spiro‐OMeTAD‐based devices when tested over 600 h.

4H-pyranylidene-based small push-pull chromophores: Synthesis, structure, electronic properties and photovoltaic evaluation

“…[13] It is worth noting that a parent dipyran-based ladder-type building block has been recently used as central donating group D in A-D-A conjugated molecules for efficient non-fullerene acceptors in OPV. [14] On the other hand, the system 2,2',6,6'-tetraphenyldipyranylidene has been used as holetransporting material for hybride perovskite solar cells, [15] and as an efficient hole-collecting interfacial layer in organic solar cells based on poly(3-hexylthiophene):phenyl-C61-butyric acid methylester (P3HT:PCBM). [16] Within this context, and having in mind our experience with the synthesis and characterization of push-pull systems featuring the 4H-pyranylidene fragment for optical applications and DSSCs, [4;6a,c,d;9b,c,e] we present here the synthesis and the electronic properties of four novel small push-pull conjugated molecules.…”

Insight into the semiconducting performance of tetraphenyldipyranylidene derivatives in organic field‐effect transistors

“…The results of photo-OFETs can represent new electronic devices. Also, the studied molecules can be used as a hole transport material in various types of electronic devices, including PSCs, organic solar cells, and organic LEDs (OLEDs) [15][16][17].…”

“…In 1970, the initial synthesis of DPPh was reported by Hunig et al [14] applied as organic material in OFETs, organic bulk-heterojunction solar cells, and perovskite solar cells (PSCs) [9,15,16]. In 2009, it was considered as an organic semiconductor layer in OFET device by Yamashita et al [9] They investigated the relationship between the electronic properties and chemical structure of DPPh in the FETs.…”

Twisted One-Dimensional Charge Transfer and Related Y-Shaped Chromophores with a 4H-Pyranylidene Donor: Synthesis and Optical Properties

“…Concerning donor units, the proaromatic character 9 of pyranylidene moiety, and the subsequent gain in aromaticity along the ICT, has turned this fragment into a versatile building block, widening their use in the field of NLO, 9,10 but also in different materials research areas such as dye-sensitized solar cells (DSSCs), 11 organic light-emitting diodes (OLEDs), 12 organic photovoltaics (OPV) 13 or hole-transporting materials for perovskite solar cells, 14 because the special electron-donating ability and chemical stability of this moiety. 15 Having in mind the two approaches above mentioned (multidimensional charge-transfer and twisted chromophores) and taking advantage of our consolidated experience in the synthesis of D−p−A systems with the 4H-pyranylidene as donor moiety, 9,10a,b,e,11b,15 we submit the design, synthesis and characterization of three series of molecules (Chart 1) for their study as second-order NLO chromophores.…”

“…Concerning donor units, the proaromatic character 9 of the pyranylidene moiety, and the subsequent gain in aromaticity along the ICT, has turned this fragment into a versatile building block, widening their use not only in the field of NLO 9 , 10 but also in different material research areas such as dye-sensitized solar cells (DSSCs), 11 organic light-emitting diodes, 12 organic photovoltaics (OPV), 13 or hole-transporting materials for perovskite solar cells 14 because of the special electron-donating ability and chemical stability of this moiety. 15 …”