Many efforts have been made towards improving perovskite (PVK) solar cell stability, but their thermal stability, particularly at 85 °C (IEC 61646 climate chamber tests), remains a challenge. Outdoors, the installed solar cell temperature can reach up to 85 °C, especially in desert regions, providing sufficient motivation to study the effect of temperature stress at or above this temperature (e.g., 100 °C) to confirm the commercial viability of PVK solar cells for industrial companies. In this work, a three-layer printable HTM-free CH NH PbI PVK solar cell with a mesoporous carbon back contact and UV-curable sealant was fabricated and tested for thermal stability over 1500 h at 100 °C. Interestingly, the position of the UV-curing glue was found to drastically affect the device stability. The side-sealed cells show high PCE stability and represent a large step toward commercialization of next generation organic-inorganic lead halide PVK solar cells.

Tin-doped indium oxide (ITO) sputtering is known as a damaging cause on organic hole transporting material in solar cells. In order to gain more insights into the reasons for poor device performance of perovskite solar cells by the ITO sputtering on Spiro-OMeTAD, here we present an in-depth study by I−V simulation analysis using corresponding equivalent circuit models. First, experimental I−V data were obtained for the perovskite solar cells with ⟨FTO/TiO 2 (dense)/ TiO 2 (mesoporous)/CH 3 NH 3 PbI 3 /Spiro-OMeTAD/ITO/Au⟩ configuration. An Au layer (t = 50 nm) was deposited on the ITO as a contact layer. The simulation studies indicated that sputtering of ITO onto Spiro-OMeTAD introduced a reverse Schottky diode and an additional diode to the device that could be relating the sputtering damage of the Spiro-OMeTAD layer. By considering the parameter of the reverse diode element as a function of sputtering time, it was found that the barrier height of the reverse Schottky diode was enhanced by the sputtering damage against Spiro-OMeTAD, which could be the key reason for the reduced fill factor of the devices.

Nanocrystalline TiO2 photoanodes were prepared on a conductive indium–tin oxide coated polyethylene naphthalate (ITO-PEN) plastic substrate by the doctor-blade method to fabricate flexible dye-sensitized solar cells (DSCs). The surface of the photoanode was coated with Mg(OH)2 by electrodeposition and the deposition time was systematically varied (2, 4, 6, 8, and 10 min). Electrodeposited Mg(OH)2 was confirmed by IR and energy dispersive X-ray (EDX) analysis. The surface morphology was studied by scanning electron microscopy. The internal surface area of TiO2 was studied against the deposition time by taking into account the projected surface area of the photoelectrode and it shows that the internal surface area of the photoelectrode was reduced as the Mg(OH)2 deposition time increased. The performance of flexible DSCs on various deposition times of Mg(OH)2 was evaluated on the basis of their photocurrent density–voltage characteristics. Among the deposition times, 2 min showed the best performance in V oc on a treated flexible DSC, with resulting 847 mV and a photocurrent density of 7.13 mA/cm2, providing an overall light-to-electricity conversion efficiency of 4.01%. This photovoltage is among the highest attained for a flexible DSC to date. This notable increment in V oc at a thin layer of Mg(OH)2 was attributed to the suppression of recombination of photogenerated electrons via the exposed surface of ITO as well as TiO2 without influencing the internal surface area of the photoanode significantly.

Thin film bismuth vanadate (BiVO 4 ) photoelectrodes are prepared by aerosol-assisted (AA)CVD for the first time on fluorinedoped tin oxide (FTO) glass substrates. The BiVO 4 photoelectrodes are characterised by X-ray diffraction (XRD), Raman spectroscopy (RS), and energy-dispersive X-ray (EDX) spectroscopy and are found to consist of phase-pure monoclinic BiVO 4 . Scanning electron microscopy (SEM) analysis shows that the thin film is uniform with a porous structure, and consists of particles approximately 75À125 nm in diameter. The photoelectrochemical (PEC) properties of the BiVO 4 photoelectrodes are studied in aqueous 1 M Na 2 SO 4 and show photocurrent densities of 0.4 mA cm À2, and a maximum incident-photon-to-electron conversion efficiency (IPCE) of 19% at 1.23 V vs. the reversible hydrogen electrode (RHE). BiVO 4 photoelectrodes prepared by this method are thus highly promising for use in PEC water-splitting cells.

TiO 2 electrodes are deposited on FTO-glass substrates at 350 and 400 8C by aerosol-assisted chemical vapour deposition (AACVD) and the deposited TiO 2 electrodes are irradiated with microwave radiation (2.45 GHz) at various percentages (10, 25, 50, and 100%). X-ray diffraction (XRD) pattern shows that the deposited electrodes have anatase phase TiO 2 oriented in the (101) direction, and the crystallinity of these electrodes increases after microwave treatment. Field emission gun scanning electron microscopy (FEG-SEM) surface topography analysis proves the preservation of the nanostructure after exposure to various percentages of microwave radiation. The photoelectrochemical (PEC) studies prove a threefold enhancement of photocurrent density of AACVD-produced TiO 2 electrodes after 100% microwave irradiation. This improved performance of PEC properties is attributed to improvements in the crystallinity and the particle-necking properties. The results presented demonstrate that microwave processing is a promising alternative method to conventional sintering for TiO 2 photoanodes.

Perovskite solar cells (PSCs) are attracting widespread attention due to their exceptional photovoltaic performance and their potential for large‐scale production via low‐cost, high‐throughput roll‐to‐roll (R2R) methods. Full realization of this production approach requires replacement of the evaporated metal electrode commonly used in PSCs. Here, a novel vacuum‐free R2R‐compatible method is introduced to fabricate and deposit printed electrodes based on electrically conductive pastes, which avoids potential loss of PSC performance due to solvent migration from the pastes. Flexible R2R‐fabricated PSCs with record power conversion efficiencies (PCEs) of up to 16.7% are produced by vacuum‐free deposition of all functional layers, apart from the transparent conductive electrode. This performance compares very favorably with that of control flexible PSCs comprising an evaporated gold electrode, which displays PCEs of up to 17.4%. Furthermore, the PSCs comprising a printed electrode demonstrate outstanding operational and mechanical stability, with negligible loss of PCE after 24 h of continuous 1‐sun illumination and retention of more than 90% of their initial PCE after 3000 cyclic bends.

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In this article, we demonstrate for the first time a mesoscopic printable perovskite solar cell (PSC) using NiO as the hole transporting material and low-temperature processed carbon as the counter electrode. A single deposition method assisted by N blow drying was used for the deposition of MAPbI on a TiO/ZrO/NiO screen-printed electrode. As the final step a low-temperature processing (i.e. 75 °C) carbon counter layer was fabricated on MAPbI by a blade coating method. It is found that the capping layer thickness of MAPbI has a significant effect on the device efficiency, especially when NiO is introduced as a hole transporting material into the structure. Electrochemical impedance spectroscopy demonstrates good charge transport characteristics for the device with a thin MAPbI capping layer obtained by the N blow drying method. Our best performing device demonstrated a remarkable photovoltaic performance with a short-circuit current density (J) of 22.38 mA cm, an open circuit voltage (V) of 0.97 V, and a fill factor (FF) of 0.50 corresponding to a photo-conversion efficiency (PCE) of 10.83%. Moreover, the un-encapsulated device exhibited advantageous stability over 1000 h in air in the dark.