The team led by Oak Ridge National Laboratory’s Jun Xu discovered the technology substantially overcomes the problem of poor transport of charges generated by solar photons.
These charges, negative electrons and positive holes, typically become trapped by defects in bulk materials and their interfaces and degrade performance.
“To solve the entrapment problems that reduce solar cell efficiency, we created a nanocone-based solar cell, invented methods to synthesize these cells and demonstrated improved charge collection efficiency,” Xu, a member of ORNL’s Chemical Sciences Division, said.
The new solar structure consists of n-type nanocones surrounded by a p-type semiconductor. The n-type nanoncones are made of zinc oxide and serve as the junction framework and the electron conductor.
The p-type matrix is made of polycrystalline cadmium telluride and serves as the primary photon absorber medium and hole conductor.
With this approach at the laboratory scale, Xu and colleagues were able to obtain a light-to-power conversion efficiency of 3.2 percent compared to 1.8 percent efficiency of conventional planar structure of the same materials.
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