Perovskite with the quantum dots ensures world-class efficiency and safety at the atmospheric environment

Photo provided : Korea Institute of Machinery and Materials (KIMM)

Korea Institute of Machinery and Materials (KIMM) under the Ministry of Science and ICT announced solar cell manufacturing technology secured with worlds best level of efficiency and safety at the atmospheric environment with the Perovskite Quantum Dot (PQD).

Hyung-cheol Shim a senior researcher at the Nano-Convergence Manufacturing Systems Research Division succeeded in producing solar cells that stably maintain with 16% efficiency in maximum of 1000 hours at the atmospheric environments by utilizing cation exchange phenomenon occurs in Perovskite Quantum Dot solar cells double-layer thin film.

The more semiconductors property is excelled the solar cells light absorbers has difference in level of absorbing sunlight from ultraviolet rays to visible rays and infrared rays. Therefore various attempts have been made to stack various layers of different material properties of semiconductor materials in order to create light absorbers that can utilize sunlight more widely.

The quantum dot which is in the limelight as the next generations solar cell is very small semiconductor crystal particle less than 10 nano-meters. The semiconductor properties can be adjusted simply by adjusting the size without changing the composition or components of the material. The manufacturing process is also relatively simple. In order to make the existing Perovskites solar cell the Perovskite precursor must be applied on the board and crystallized through a high-temperature heat treatment process of over 200 degrees Celsius.

However by dispersing quantum dot which are already in a fine crystal state to the solvent and convert it into a liquid and then spray or coat it on to the board solar cells can be made. The research team created a Perovskites Quantum Dots solar cell with a double-layer thin film structure made of different cations (cesium lead iodide and formamidine).

The Quantum Dot solar cells have defects in the process of exchanging ligands which covering the surface of cation are dropped out. The research team improved stability by designing formamidine ions to move and repair the defects themselves.

For this reason the Perovskite Quantum Dot solar cell with double-layer thin film structure was able to maintain longer performance than the existing Perovskite single-layer thin film structures light absorber.

Using this technology it is expected that solar cell absorbers can be made only in solution process instead of in conventional thermal process and production costs can be significantly reduced.

It can also be used as a way to increase the efficiency of existing systems by using Perovskites property of lighter and flexible than the silicon and reinforcing absorbers on top of existing silicon solar cells as well as spreading electricity in rugged areas where solar cells are difficult to be installed.

In addition the solar cells atmospheric safety can be maximized without additional coating or sealing technology by utilizing quantum dots where defects are minimized by cation-exchange.

Hyung-cheol Shim a senior researcher of KIMM said We are expecting to catch two birds with one stone which are efficiency and safety of Perovskite Quantum Dot solar cells just with the simple manufacturing process. and added Through the subsequent research we will strive to enhance the solar cells economical efficiency and contribute to our countrys goal of achieving carbon neutrality.

Meanwhile the research was carried out with the support of Ministry of Science and ICT to KIMMs main projects Nano-based Omnitex Manufacturing Technology Development the international cooperation technology development business of Ministry of Trade Industry and Energys Quantum Structure-based High Efficiency and Ultra-Low-Efficiency Solar Cell Technology Development and Alchemist projects Development of Soft Smart Suit Suitable for Rapid detection and Blocking Hazardous Substances. The results of the research were published in Applied Materials and Interfaces(ACS)s Vol. 12 No. 51 Highly Efficient and Air-Stable Heterostructured Perovskite Quantum Dot Solar Cells Using a Solid-State Cation-Exchange Reaction.

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