Abstract Colloidal semiconductor nanocrystals (NCs) have garnered significant attention as promising photovoltaic materials due to their tunable optoelectronic properties enabled by surface chemistry. Among them, AgBiS 2 NCs stand out as an attractive candidate for solar cell applications due to their environmentally friendly composition, high absorption coefficients, and low‐temperature processability. However, AgBiS 2 NC photovoltaics generally exhibit lower power conversion efficiency (PCE) compared to other NC‐based devices, primarily due to numerous surface traps that serve as recombination sites, leading to a short diffusion length for free carriers. To address this challenge, this work develops donor and acceptor blended (D/A) AgBiS 2 films. Through ligand modulation, this work formulates acceptor and donor AgBiS 2 NC inks with suitable electrical band alignment for charge separation, while ensuring that they are fully miscible in the same solvent. This enabled the fabrication of high‐quality, thickness‐controllable D/A‐blended junction films. This work finds that this approach effectively facilitates carrier separation, leading to an enhanced carrier lifetime and diffusion length. As a result, using this approach, this work achieves AgBiS 2 films that are twice as thick in solar cell applications compared to conventional devices, leading to improvements in current density and a solar cell PCE of 8.26%.

The coupled electronic and structural transitions in metal-insulator transition (MIT) hinder ultrafast switching and ultimate endurance. Decoupling these transitions and achieving a zero-strain electronic MIT can overcome the fundamental limitations of MIT in solid materials. Here, this study demonstrates that iso-valent Ti dopants in supercooled VO₂ epitaxial films cause MIT with minimal hysteresis without changing unit-cell volume and crystal symmetry. The Ti dopants in the VO₂ lattice locally alter the configuration of V-V pairs, where the long-range ordering in V-V pairs is disrupted, and the nano-domains of V-V dimers are formed. Strikingly, these local V-V dimers persist even above the electronic transition temperature (T_MI), facilitating the zero-strain electronic MIT with nanoscale structural heterogeneity. The geometrically compatible interface between insulating and metallic phases drastically enhances switching speed and endurance during electrically and optically driven zero-strain MIT. This discovery offers a fresh perspective on the scientific understanding of MIT and the improved functionality in terms of device speed and reliability by decoupling electronic and structural transitions.