Chemical doping has been widely used to finely tune the electrical properties of organic hole-transporting materials (HTMs) that find widespread applications in perovskite solar cells (PSCs). Here, to shed light on the precise role of chemical p-doping in affecting the charge-transport properties of HTMs and photovoltaic performance of PSCs, two kinds of representative dopants, including lithium bis(trifluoromethane)sulfonimide (LiTFSI) and two Co(III) complexes tris[2-(1H-pyrazol-1-yl)-4-tert-butylpyridine]cobalt(III)tris[bis(trifluoromethylsulfonyl)imide] (FK209) and tris[2-(1H-pyrazol-1-yl)pyridine]cobalt(III)tris[bis(trifluoromethylsulfonyl)imide] (FK102), are employed as the p-type dopant models to dope the 2,2′,7,7′-tetrakis[N,N-di-p-methoxyphenylamine]-9,9′-spirobifluorene (spiro-OMeTAD) HTM. Both dopants can facilitate the generation of oxidized spiro-OMeTAD radical cation and improve hole mobility. Co-doping of FK209 and LiTFSI is necessary to achieve an optimal doping property and best device performance with power conversion efficiency of 17.8% compared to that of the FK209-doped device (13.5%) and the LiTFSI-doped device (15%). UV–vis absorption, space-charge-limited current measurements, and steady-state and time-resolved photoluminescence measurements have confirmed that with the co-doping of the two kinds of p-dopants in a proper ratio the doped spiro-OMeTAD exhibits a high charge carrier mobility and charge carrier transfer/collection capability.

Water splitting is a promising technique for clean hydrogen energy harvesting. The creation of cost-effective electrocatalysts with improved hydrogen evolution reaction (HER) activity and stability is crucial in realizing persistent hydrogen evolution by reducing the reaction overpotential and minimizing energy consumption. Herein, we present the preparation of alloyed PtM (M = Cr, Fe, Co, Ni, Mo) modified titanium (Ti) mesh by a simple electrodeposition method, aiming at hydrogen generation from seawater splitting. The preliminary results indicate that the Ti/PtM electrodes feature markedly reduced onset overpotentials and Tafel slopes as well as significantly increased exchange current densities compared with pristine Pt electrodes, arising from the incorporation of secondary M atoms into the Pt lattice for alloying effects. Moreover, the competitive dissolution reaction between guest M species to Pt with Cl₂ in seawater is beneficial for enhancing the long-term stability of resultant PtM alloy electrodes. The optimized PtMo alloy electrode maintains 91.13% of the initial current density upon 172 h operation in real seawater, making it promising in practical applications.