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Abstract The versatile Bell-Evans-Polanyi (BEP) relation stipulates the kinetics of a reaction in terms of thermodynamics. Herein, we establish the BEP relation for the hydrogen evolution reaction (HER) from fundamental electrochemical principles leveraging the Butler-Volmer relation for a one-step, one-electron process and the transition state theory. Based on first-principles investigations of HER mechanisms on fourteen metal electrodes, we firmly justify the BEP relation solely using an easy-to compute hydrogen adsorption free energy and universal electrochemical constants. 

Recent manufacturing of perovskite solar cells (PSC) is moving beyond a spin coating technique. Among several new methods of the large‐area PSCs, inkjet printing (IJP) has emerged as a promising alternative to spin coating due to the high degree of control on printed film area and low material waste. In the IJP of PSCs, one important question is how to remove redundant excess solvent and facilitate the crystallization of the perovskite phase. Along with IJP, an antisolvent bathing is employed. This work reports how the IJP parameters and antisolvent bathing compositions affect the microstructure and initial efficiency of inkjet‐printed PSCs. The halide perovskite films are submerged in the antisolvent of different temperatures to observe the formation of an intermediate phase and the evolution of perovskite phase. By observing the phase evolution using X‐Ray diffraction, an optimized antisolvent bath duration is achieved for diethyl ether (DE) condition. An enhanced power conversion efficiency (PCE) and larger grain size with two sequential passes of inkjet‐deposited perovskite are also reported, and the dissolution of homogeneous nucleation sites as a mechanism for larger grains is proposed. Finally, with multipass IJP and cold antisolvent DE bathing, a champion device with 15.02% PCE is achieved.