Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV19)
Publication date: 6th February 2020
The metioric rise in operating efficiency of perovskite solar cells (PSC) from ca. 11% in 2012 [1] to 21% in 2017 [2] has generated enormous interest in these devices. In addition, whilst a 1 year PSC device has just been reported [3], issues remain regarding their ambient stability. There is also a need to consider lead-free PSC devices which has led researchers to substitute Pb with other metals (e.g. tin) and the addition of other ions (e.g. Cs etc. [4]) to try to improve stability. In this poster, we set ourselves the challenge of answering the question:
Is it possible to deposit perovskite without using toxic solvents?
In practice, this has meant that we could not even dissolve the perovksite pre-cursors. The perovskite systems that we have studied are similar to first perovskite devices by Miasaka et. al. [1]; i.e. modified dye-sentized solar cells. So we have termed these as “hybrid” perovskite devices as they are typically largely unconnected perovskite nanoparticles which require either further chemical sintering or a thick percolating electrolyte to function. By synthesizing perovskite nanoparticles through a hybrid sol gel approach (but without the use of organic capping ligands that usually limit the growth of the material in the three dimensions) we have been able to improve the ambient stability of organolead perovskites. We have even been able to synthesize 100% organotin perovskite material in air. This has been achieved through production of large perovskite nanoparticles for which thermal analysis suggests increased binding of the organic cation. Raman data show the incorportation of Al2O3 shifts the spectra suggesting it acts as a hybrid-3D mesoporous stack. Synchotron studies of crystal stability, induced laser current mapping (LBIC) measurments and superoxide generation measurments are coupled to thermogravimetric analysis to show that these hybrid perovskites demonstrate improved ambient and thermal stability. This poster work will discuss the benefits of using such a synthesis for print deposition techniques; e.g. compositional control in sintered perovskite thin films, as well as upscaling and green chemistry recycling issues.
We gratefully acknowledge funding from EPSRC EP/M015254/2 (AC, EWJ), EP/P030068/1 (DMR), the Welsh Govt. for Sêr Cymru (PJH) and EU SPARC-II (RA, LF, RJH, CK).