Near-infrared colloidal quantum dots for efficient and durable photoelectrochemical solar-driven hydrogen production

Solar energy offers a huge potential for global supply of clean and sustainable energy, reducing our dependence on fossil fuels and decreasing carbon dioxide (CO2) emissions. [1-7] Photoelectrochemical (PEC) solar-driven hydrogen (H2) production, which converts solar energy into H2 using semiconductors as active materials, is considered as a promising route, because H2 is a solar fuel, which combines the advantages of high energy storage densities, ease of transportation, cost-effectiveness, [8] and generating water as the only byproduct of H 2 use. [9] PEC cells perform redox reactions driven by electron-hole pairs created by incident photons, namely, the holes oxidize water/hole scavengers at the surface of the photoanode, and the electrons migrate to the counter electrode to reduce water and produce hydrogen. [10] The ideal PEC cell is composed of inexpensive semiconducting materials with proper electronic band structure, leading to strong sunlight absorption, effective charge separation, and high photochemical stability.