Direct Solar Water Splitting for Green Hydrogen Generation Project at IIT Madras

Direct solar water splitting for green hydrogen generation

Objective

• To develop large area (100 cm?) solar water splitting devices (assisted/unassisted) using stable Cs2MXe semiconductors that can generate at least 300 to 500 mA photocurrent and with 1000 hours of operational stability under simulated sunlight, Design/development of highly efficient reactors using combination of simulation of device properties and fluid transport.

Description

• The material to be used in this work is based on the vacancy ordered perovskite Cs2PtI6 and its analogues with other low cost transition elements replacing Pt. Conventional photoelectrochemical cells employ oxides or silicon absorbers to absorb the sunlight, Oxides have large bandgap and poor optoelectronic properties and hence they do not absorb significant portion of the sunlight and show low efficiencies. Silicon on other hand is a good semiconductor, but degrades quickly and so it requires additional pinhole free protection layer. Typically the protection layer is deposited by expensive atomic layer deposition technique which increases the cost, In this work, as our vacancy ordered perovskite is ultrastable and absorbs entire visible spectrum of sunlight, it does not require any additional protection layer. This material couples the stability of oxides and the optical/electronic properties of silicon. The proposed work involves the deposition of defect free material using thermal evaporation, so the performance is expected to be very high and expected to surpass most of the prototypes developed using oxide absorbers, We will also carry out systems level simulation to design high performance device configuration with optimal absorption of light, charge transport within semiconductors, water/electrolyte flow, and mass transport of ions/gases

Impact

• The proposed prototype will help convert the solar energy directly to fuels. Here we will build photoelectrochemical solar fuel systems, where energy of the sunlight will be used to split water to generate hydrogen.