Organic-inorganic halide perovskites have created a breakthrough in the field of solar cells because of their low cost, low temperature processibility and  excellent optoelectronic properties. However, the instability of  organic-inorganic halide perovskites to moisture is currently a huge challenge in the  field of  perovskite solar cells and needs to be addressed to translate the perovskite technology from the laboratory bench to large scale industrial practice.  Currently, all the lab scale perovskite cells are fabricated in controlled glove box atmosphere with less than 1 % relative humidity to prevent their deterioration under moisture.

In this work, a novel concept of protecting the perovskite using a highly conductive composite of a layered material and a hole transporting polymer is presented. The excellent charge transport properties of the composite coating allow the  use of thick coating on the perovskite, creating extremely high length scales for moisture diffusion through composite. The composite coating developed in our work, could be extended to lead-free organometallic perovskites that are both moisture and oxygen sensitive.  The deposition of gold as a counter electrode for the lab scale perovskite cells is usually performed by thermal evaporation in a bell jar evaporator. This process is time consuming, energy intensive and not viable to scale up. Our approach involving lamination of individual electrodes, enables a much facile low cost process for fabricating perovskite solar cells.

Our results and observation on polymer composites as protective coatings for perovskite and on  laminating electrodes show high promise for the  scalability and low cost fabrication of perovskite cells under atmospheric conditions  (60 -70 % relative humidity). In addition, the degradation mechanisms involving both moisture and oxygen in the presence of UV light irradiation will be discussed.