IBM Materials Science researchers, in conjunction with partners from Solar Frontier, Tokyo Ohka Kogyo (TOK) and DelSolar, have developed an efficient and affordable PV cell that is made from abundant natural materials, and has already crushed the world record for PV solar-to-electric power conversion efficiency using earth-abundant materials.
The team from IBM wanted to create a technology that combined the virtues of being highly efficient, cheaply scalable, and easily made from abundant materials.
Made from copper, zinc, and tin and referred to as CZTS, the IBM thin-film device achieved a world-record PV solar-to-electric power conversion efficiency for solar PV cells composed of earth-abundant materials — 11.1 percent, which is a thwacking 10 percent better than any previous report. It can also be made from simple ink-based techniques such as printing or casting.
IBM explain their impetus for undertaking this research, and why they felt it necessary:
Currently, the most widespread PV semiconductors, made of crystalline silicon, are abundant and highly efficient. They’re in panels used for everything from home electricity to the International Space Station. However, they have extremely high material purity requirements (>99.9999 percent!), and the wafers are typically cut from large solid ingots and wired in series to form PV modules – making it expensive and difficult to upscale.
Other thin-film chalcogenide materials used in PV cells, such as Cu(In,Ga)(SSe)2 (CIGS) and CdTe, have been developed to a performance level close to that of silicon, with inherently more scalable processing. They are directly deposited on large-area, low-cost substrates such as glass, metal or plastic foil. While CIGS and CdTe are easy to integrate into buildings and consumer products, their compounds contain rare and expensive elements that increase cost and limit their manufacturing levels to less than 100 Gigawatts per year (worldwide continuous electricity consumption is 15 Terawatts – 150 times greater than the level of what these CIGS can produce).
Subsequently, IBM has created its new solar cell, which could potentially yield up to 500 GW a year. The researchers will now focus on further increasing the device efficiency, and transfer the technology to environmentally-friendly, high-throughput industrial manufacturing, with the hope that within the next few years this new class of photovoltaic material will be widely available as a lower-cost answer to solar electricity.
Source: IBM Research News