Samrana Kazim – Rational Design of charge selective contacts for Metal Halide Perovskite Solar Cells

Dr. Samrana Kazim, BCMaterials-Basque center for materials, applications & nanostructures, Leioa, Spain.

Organo metal halide perovskite based thin film solar cells (PSCs) have shown the best performance in solid state based hybrid solar cells and the power conversion efficiency (PCE) of mesoporous-type perovskite solar cells (PSCs) have made a striking jump from merely 3.8% to 25.2% in a decade through compositional and interface engineering of perovskite materials, design and optimization of charge selective contacts, deposition methods and device architectures.
As of now, device structure adopted for high efficiency PSCs are based on either mesoporous type or planar type n-i-p configuration, where perovskite is sandwiched between the n-type electron transporting layer(ETL) and p-type hole transporting layer (HTL). But, mesoporous type requires high temperature sintering of mesoporous TiO2 layer for the better performance, which limits its application in flexible device and increases the cost. To overcome this problem, planar type PSCs have been fabricated using low cost, easy synthesis and low temperature treated ETL. On the other hand, the presence of mesoporous scaffold reduces the hysteresis and increases the stability of PSCs. So far TiO2 was the most extensively used ETL in planar type PSCs, however it exhibits very low electron mobility compare to state of the art HTL and thus charge accumulation occurs at the TiO2/perovskite interface leading hysteresis and low PCE. Recently, to replace TiO2, solution processed SnO2 has been used as ETL for planar type PSCs due to its high electron mobility and more optical transparency in UV part and better matching energy level relative to perovskite. Nevertheless, the PCE of these planar-type solar cell is still low along with high hysteresis compared to mesoporous based ones likely due to charge accumulation at SnO2/perovskite interface triggered by low electron mobility of SnO2.
Thus in the present talk, I will show some of our results on modified SnO2 to increase the electron mobility and shift of fermi level towards conduction band and thus increases the open circuit voltage and improve the electron extraction thus improve the performance and the stability and reduces the hysteresis of PSCs.
Besides, to replace the state of the art Spiro-OMeTAD as HTM, different type of new organic small molecules, organometallic complexes have been designed and synthesized and implemented in different device architecture. The role of HTM to improve the performance and stability of the PSCs has been investigated in different device configuration. Further, the advantages, disadvantages, and peculiarities of different types of HTM employed in PSCs will be discussed, and how they can be further modified and optimized.

Biography

Dr. Samrana Kazim obtained her Master degree (M.Sc) and doctoral degree(Ph.D.) in Materials chemistry at JMI university, New Delhi (India). After finishing her Ph.D. in 2008, she moved to Institute of Macromolecular Chemistry (IMC), Prague on IUPAC/UNESCO fellowship. Later, she became a staff scientist in IMC before moving to corporate research. Before joining BCMaterials as Senior scientist, she worked as a permanent senior scientist at Abengoa Research, a corporate research centre of Abengoa from 2013-2017. She has published >40 research articles in reputed journals in the field of material science, energy and nanotechnology, co-authored 2 book chapters and inventor of numerous patents in the field of energy conversion and storage. Her field of research interest includes Electro-optical characterization of organic semiconductors, perovskite solar cells, hybrid inorganic-organic nanocomposites and plasmonics.