Rubidium (Rb) is explored as an alternative cation to use in a novel multication method with the formamidinium/methylammonium/cesium (Cs) system to obtain 1.73 eV bangap perovskite cells with negligible hysteresis and steady state efficiency as high as 17.4%. The study shows the beneficial effect of Rb in improving the crystallinity and suppressing defect migration in the perovskite material. The light stability of the cells examined under continuous illumination of 12 h is improved upon the addition of Cs and Rb. After several cycles of 12 h light–dark, the cell retains 90% of its initial efficiency. In parallel, sputtered transparent conducting oxide thin films are developed to be used as both rear and front transparent contacts on quartz substrate with less than 5% parasitic absorption of near infrared wavelengths. Using these developments, semi‐transparent perovskite cells are fabricated with steady state efficiency of up to 16.0% and excellent average transparency of ≈84% between 720 and 1100 nm. In a tandem configuration using a 23.9% silicon cell, 26.4% efficiency (10.4% from the silicon cell) in a mechanically stacked tandem configuration is demonstrated which is very close to the current record for a single junction silicon cell of 26.6%.

The interdigitated back contact (IBC) solar cells developed at the Australian National University have resulted in an independently confirmed (Fraunhofer Institut für Solare Energiesysteme (ISE) CalLab) designated‐area efficiency of 24.4 ± 0.7%, featuring short‐circuit current density of 41.95 mA/cm2, open‐circuit voltage of 703 mV and 82.7% fill factor. The cell, 2 × 2 cm2 in area, was fabricated on a 230 µm thick 1.5 Ω cm n‐type Czochralski wafer, utilising plasma‐enhanced chemical vapour deposition (CVD) SiNx front‐surface passivation without front‐surface diffusion, rear‐side thermal oxide/low‐pressure CVD Si3N4 passivation stack and evaporated aluminium contacts with a finger‐to‐finger pitch of 500 µm. This paper describes the design and fabrication of lab‐scale high‐efficiency IBC cells. Characterisation of optical and electronic properties of the best produced cell is made, with subsequent incorporation into 3D device modelling used to accurately quantify all losses. Loss analysis demonstrates that bulk and emitter recombination, bulk resistive and optical losses are dominant and suggests a clear route to efficiency values in excess of 25%. Additionally, laser processing is explored as a means to simplify the manufacture of IBC cells, with a confirmed efficiency value of 23.5% recorded for cells fabricated using damage‐free deep UV laser ablation for contact formation. Meanwhile all‐laser‐doped cells, where every doping and patterning step is performed by lasers, are demonstrated with a preliminary result of 19.1% conversion efficiency recorded. Copyright © 2014 John Wiley & Sons, Ltd.

No abstract

No abstract

No abstract