NIR Photoresponse of Perovskite Solar Cells with Titanyl Phthalocyanine

Abstract

The effect of titanyl phthalocyanine TiOPc in the methylammonium lead triiodide (MAPbI 3) perovskite based solar cells is studied. The photovoltaic output of cells at low intensity illumination with l max = 840 nm is greatly enhanced when using TiOPc as a NIR-absorbing hole conductor. Compared to the reference cells with a standard cuprous iodide CuI as a hole-transporting layer, the photocurrent increases by a factor of 15, so that the narrow-band power conversion efficiency (PCE) exceeds 2 %. It should be pointed out that the irradiation wavelength lies beyond the intrinsic absorption of MAPbI 3 or any other material in the device scheme except TiOPc. The improvement is associated with the photoactivity of TiOPc molecules in the near infrared region due to the largely splitted Q-band, as confirmed by the dependence of parameters on the polymorph transition in the TiOPc films.

Molecular optical filtering in perovskite solar cells

“…Archetypal perovskite solar cells with a scheme shown in Fig. 2 were obtained by vacuum thermal evaporation on a modernized VUP-5 M setup at residual pressure of 10 -6 Torr and then investigated in line with the experimental protocols of our earlier studies [2,[18][19][20]. The schematic of the cells is similar to that obtained very recently in [21] using fully vacuum-based processes, except for the HTL material.…”

“…A perovskite photoabsorber methylammonium lead iodide, MAPbI 3 consisting of lead iodide PbI 2 (99.995%, Aldrich) and iodide methylammonium MAI (98%, Aldrich) was fabricated by simultaneous deposition of the components from two sources. Titanyl phthalocyanine TiOPc (95%, Alfa Aesar) [19,[22][23][24] and fullerene C 60 (99.9%, Aldrich) [2,25] were deposited before and after MAPbI 3 , respectively, and served as auxiliary photoactive and/or charge-carrier layers. The choice of materials was determined by the need to modify the interfaces between the perovskite photoabsorber and the adjacent charge-carrier layers, which is essential for the operation stability of PSC under load.…”

“…By 'modification', we mean minimizing the defects (traps) [26] that impede the transport of photogenerated charge carriers. The materials used provide a better barrier against migration of ions than non-organic chargetransporting layers, for example, copper iodide (I), CuI, or doped metal oxide [19,27,28].…”

“…Molybdenum trioxide MoO 3 (99,998% Alfa Aesar) and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, BCP (96% Aldrich) were used as the anode and cathode buffer sublayers, respectively. The MoO 3 , TiOPc, and MAPbI 3 layers were deposited in sequence, then the sample was annealed at 150 °C during 10 min in order to optimize the phase composition of TiOPc and MAPbI 3 [19]. Silver strips (Ag, 999.9% SBRF) were then deposited on top of the asprepared multilayer structures through the shadow mask to form an array of nontransparent top electrodes with the active area of 0.15 cm 2 each.…”

Different Degradation Mechanism of CH3NH3PbI3Based Perovskite Solar Cells under Ultraviolet and Visible Light Illumination

“…对于传统有机无机杂化钙钛矿材料, 例如甲氨碘化 铅(CH 3 NH 3 PbI 3 即 MAPbI 3 ), 其能带带隙通常在 1.56～ 1.70 eV, 这意味着其可以吸收波长小于 729～785 nm 的 光子 [18][19][20] . 但是对于太阳光全光谱而言, 可见光波长通 常在 400～760 nm, 大约占到了总光谱能量的 50%左右; 而 100～400 nm 为紫外光波长区域, 大约占太阳光总能 量的 7%; 剩余的为大于 760 nm 波长的红外光区域 [21] , 该波段的光被有机无机杂化钙钛矿太阳能电池吸收的 概率较小, 另外有报道认为近红外光的辐照会对钙钛矿 太阳能电池器件性能有一定的提升 [22] .…”