Monolithic perovskite-organic tandem photo voltaic cell achieves 24.27% effectivity – pv journal International

August 20, 2024 Valerie Thompson

To overcome the operational stability problems with wide-bandgap steel halide perovskite cells, a workforce from the City University of Hong Kong designed a sequence of “multifunctional” natural redox mediators primarily based on anthraquinone, which have been in a position to “selectively cut back iodine and oxidize metallic Pb0, whereas concurrently passing on defects by tailor-made cationic substitution”.

The stability and efficiency of perovskite photo voltaic cells utilizing natural redox mediators primarily based on anthraquinone have improved, in keeping with researchers. The work features a structural evaluation and density practical idea calculations of “redox mediator / perovskite interfacial fashions to achieve insights into the roles of AQS derivatives in accelerating the general redox response and passivating perovskite”, in addition to estimating of their interactions.

“This falls largely to what we predicted after our thorough investigation of the underlying mechanism of the reason for halide segregation in broad bandgap perovskites-based photo voltaic cells beneath working situations,” Alex Jen Kwan-yue, the corresponding who authored the analysis, stated. pv journal. “After we recognized a number of potential causes, we’ve got customized an acceptable redox mediator that may not solely stabilize the halide separation, but additionally passivate the defects fashioned in the course of the processing and operation.These molecularly engineered molecules have confirmed to be very efficient in serving the aim.

For the goal perovskite photo voltaic cell machine, the redox mediator anthraquinone derivatives are added to the perovskite precursor, particularly three compounds referred to as AQSH, AQSN and AQSP. The ensuing energy conversion effectivity is nineteen.58% with a “excessive” open-circuit voltage of 1.35 V, whereas the management machine has an influence conversion effectivity of 18.68%. The goal outperformance is primarily characterised by improved open circuit voltage.

These units retain 95% of their preliminary effectivity after 500 hours of operation at most energy level. The goal short-circuit present density is 17.52 mA/cm2, with a fill issue of 82.74%.

The workforce later built-in the perovskite photo voltaic cell right into a two-terminal monolithic perovskite-organic tandem machine. The ensuing tandem cell achieved an authorized effectivity of 24.27%, an open-circuit voltage of two.151 V, a short-circuit present density of 14.36 mA/cm2, and an element of filling 81.65%. The outcomes of long-term operational stability have been “spectacular,” the workforce stated.

The single-junction perovskite broad bandgap subcell is fabricated on glass substrates pre-patterned on indium tin oxide glass with a p-type self-assembled monolayer (SAM), a perovskite movie, and a C60 layer. The perovskite precursor composition consists primarily of (Cs0.2FA0.8Pb(I0.6Br0.4)3) and MAPbCl3.

The natural subcell utilized in tandem has an effectivity of 16.62%, an open-circuit voltage of 0.840 V, a short-circuit present density of 26.58 mA/cm2, and a fill issue of 74.43%. It is a junction molybdenum oxide with indium tin oxide in a pin sort configuration on glass.

“Among tandem photo voltaic cells, perovskite-organic variants dominate because of their answer processability, extremely tunable physicochemical properties, and cost-effective uncooked supplies,” stated Jen Kwan-yue, who defined -look at selecting a perovskite-organic photo voltaic cell mixture for the tandem machine. “In addition, their flexibility and transparency open up numerous progressive functions, comparable to wearable electronics and constructing or automobile -integrated PVs. These compelling benefits drive our consideration to perovskite-organic tandem photo voltaic cells.

Looking at future analysis plans, Jen Kwan-yue stated, “Our analysis group is devoted to creating new redox mediators with improved redox capabilities, superior electrical properties , and environment friendly defect acceleration.At the identical time, we’re engaged on bettering the efficiency of perovskite-organic tandem photo voltaic cells by delicate interface engineering and molecular design for low-bandgap non-fullerene acceptors.

A derivative firm, HKTech Solar, will commercialize the expertise. It has attracted “vital funding” from traders and the federal government to develop PV merchandise, in keeping with Jen Kwan-yue.