High efficiency electrospun TiO₂nanofiber based hybrid organic–inorganic perovskite solar cell

Abstract

The good electrical and morphological characteristics of TiO₂ nanofibers and the high extinction coefficient of CH₃NH₃PbI₃ perovskite are combined to obtain a solar cell with a power conversion efficiency of 9.8%. The increase of the film thickness dramatically diminishes the performance due to the reduction in porosity of the TiO₂ nanofiber framework. The optimum device (∼413 nm film thickness) is compared to a planar device, where the latter produces higher V(oc) but lower J(sc), and consequently lower efficiency at all measured light intensities.

Carbon Nanotubes in TiO2 Nanofiber Photoelectrodes for High‐Performance Perovskite Solar Cells

“…This higher V oc value of planar devices can be associated with the lower probability of charge recombination as compared to the porous structured PSCs. These results are very consistent with recent studies on CH 3 NH 3 PbI 3 ‐based planar PSC devices 25, 58, 59. Considering the PCEs of the devices, the TiO 2 NF (≈400 nm) film was chosen for further investigations and device fabrication.…”

“…For example, the V oc of the TiO 2 NF‐only PSCs (control cell) increased from 0.87 to 0.93 V when J–V characteristics are measured without a mask, and yielding an improved PCE (9.1%). These improved values ( V oc and PCE) are comparable and similar to those reported in the literature,24, 25 suggesting that in our study, the V oc values measured with aperture mask were slightly underestimated and would be higher if no mask was applied during the J–V analysis.…”

“…We also demonstrate in this study that SWCNTs can be used as an efficient HTM in PSCs. While previous work has shown TiO 2 NF‐based PSCs can achieve PCE values of up to 9.8%25 and 13.4% for atomic layer deposited nanorods,54 in this work, our best performing PSC achieved a PCE of 14.03%.…”

“…Increasing the film thickness, which in turn lowers the PCE, is believed to be a result of the high charge recombination rate within the TiO 2 NF based devices 10, 25, 57. In contrast, the devices fabricated without TiO 2 NFs (called planar PSCs) or with thin TiO 2 NF layers (≈285 nm) showed high V oc , but their PCEs were low due to the decreased J sc and FF values.…”

Nanoscale electrode architectures for electrochemical energy conversion and storage.

“…[39] The slow dissolution of perovksites in liquid electrolytes has been identified as one of the factors limiting the performance [40] and subsequent reports have focused using solid state hole transport materials instead of liquid electrolytes. [41,42] Improvements of perovskite solar cell efficiencies over the past few years have been achieved using different anode architectures, [43][44][45] deposition methods, [46][47][48][49][50] varying the halides and organic cations in the perovskite structure, [39,51,52] and by the application of materials with improved electron and hole transport characteristics. [53,54] The deterioration of the perovskite when exposed to moisture still remains a major …”