Cu(i)-based delafossite compounds as photocathodes in p-type dye-sensitized solar cells

Abstract

The research of p-type dye-sensitized solar cells (p-DSSCs) has attracted growing attention because of the potential for integration with conventional n-type DSSCs (n-DSSCs) into the more efficient tandem-DSSCs. However, to date the performance of p-DSSCs is lagging behind that of n-DSSCs. One main reason is the lack of optimal photocathode materials. This article reviews the most recent progress in utilizing Cu(I)-based delafossite compounds, CuMO2 (M = Al, Ga or Cr), as photocathodes in p-DSSCs. As alternative materials to the commonly used NiO, the CuMO2 compounds have their intrinsic advantages such as lower valence band edge, larger optical bandgap and higher conductivity. By providing an insight into these materials and their applications in p-DSSCs, this perspective aims to stimulate more exciting research in the development of p-DSSCs as well as of tandem-DSSCs.

Combining Electron‐Accepting Phthalocyanines and Nanorod‐like CuO Electrodes for p‐Type Dye‐Sensitized Solar Cells

“…The major bottleneck of our devices evolves around the low Voc, since Jscs are comparable to CuXO2 based DSSCs. [7] Using cobalt di-tert-butyl bipyridine hexafluorophosphate [Co(dtb-bpy)3][PF6]2/3 as electrolyte is the most efficient way to overcome this limitation. [22] Under 1 sun illumination and AM 1.5 conditions, ZnPc2 DSSCs reveal higher Vocs and Jscs (251 mV and 2.35 mA/cm 2 ) than ZnPc1 DSSCs (224 mV and 1.99 mA/cm 2 ) - Figure 4 and Table 1.…”

Inorganic p-Type Semiconductors: Their Applications and Progress in Dye-Sensitized Solar Cells and Perovskite Solar Cells

“…Among them, the Cu(I)-based delafossite materials (CuMO 2 , M = Cr, Ga, Al) have shown promising results because of their deeper position of the valence band edge and optical transparency in the visible range. Moreover, in Cu(I)-based delafossite materials, that Cu 3d orbitals strongly hybridize with the O 2p orbitals, making the hole charge carriers be delocalized both on oxygen and copper atoms [84] which facilitates the hole mobility, for instance 10-10´2 cm 2 /(V¨s) for CuAlO 2 and CuGaO 2 [84][85][86]. A solid-state reaction synthesized CuAlO 2 and hydrothermally synthesized CuGaO 2 proved V oc s of 333 mV [87] and 357 mV [88], with respectively the following dye and redox mediator couples: PMI-6T-TPA and I 3´/ I´, and PMI-NDI and Co 3+ /Co 2+ (dtb-bpy).…”

Developments in and prospects for photocathodic and tandem dye-sensitized solar cells

“…As such the majority charge carriers are holes and as a result, the EF of these materials lies closer to the VB than the CB. As a critical part of the pDSC architecture, there have been review articles focussing solely on different NiO structures [36] and p-type copper delafossite materials for pDSC [30].…”

“…Developments in pDSC device efficiency are addressed below in Section 2.1 and show a rapid and dramatic increase since this first report. pDSCs have also been the subject of a number of review articles, including specialised topics such as ternary copper oxide materials [30][31][32][33][34][35][36].…”