In-situ defect passivation assisted three-step printing of efficient and stable formamidine-lead bromide solar cells

Perovskite solar cells(PSCs)emerge as the most promising photovoltaics(PV)for their high performance and potential convenient cost-effective production routes comparing to the sophomore PV technologies.The printed PSCs with simplified device architecture and fabrication procedures could further enhance the competitive strength of PSC technology.In this work,we present an in-situ defect passivation(ISDP)assisted full-printing of high performance formamidine-lead bromide(FAPbBr_(3))PSCs.Only three rapid printing steps are involved for electron transporting layer(ETL),perovskite and carbon to form a complete solar cell on the low-cost fluorine-doped tin oxide(FTO)substrate.Long-chain polymer monomethyl ether polyethylene glycol is particularly utilized as the ISDP passivator,leading to conformal coating on the rough FTO and defect passivation for both ETL and perovskite during printing.A high efficiency of 10.85%(certified 10.14%)and a high V_(oc)up to 1.57 V are achieved for the printed device.The unencapsulated PSCs maintain above 90%of the initial efficiency after continuously heating at 85℃for 1000 h and over 80%of the efficiency after the maximum power point tracking for 3500 h.The fully printed semitransparent PSCs with carbon grids(CGs)show average visible light transmittance over 33%and an efficiency of 8.81%.

Universal Encapsulation Adhesive for Lead Sedimentation and Attachable Perovskite Solar Cells with Enhanced Performance

In this work,a modified polyurethane adhesive(PUA)was prepared to realize a convenient encapsulation strategy for lead sedimentation and attachable perovskite solar cells(A-PSCs).The modified PUA can completely self-heal within 45 min at room temperature with an efficient lead ion-blocking rate of 99.3%.The PUA film can be coated on a metal electrode with slight efficiency improvement from 23.96%to 24.15%.The thermal stability at 65℃and the humidity stability at 55%relative humidity(RH)are superior to the devices encapsulated with polyisobutylene.The PUA film has strong adhesion to the flexible substrate and the initial efficiency of the flexible perovskite module(17.2%)encapsulated by PUA remains 92.6%within 1825 h.These results suggest that PUA encapsulation is universal for rigid and flexible PSCs with enhanced stability and low lead hazards.Moreover,it was found that flexible PSCs can be well attached to various substrates with PUA,providing a facile route for the A-PSCs in various scenarios without additional encapsulation and installation.

Low-cost biodegradable lead sequestration film for perovskite solar cells

Despite the high efficiency that has been achieved for the perovskite solar cells(PSCs),the hazardous lead leakage from the perovskite absorber layer is one of the crucial barriers still hindering its penetration into the commercial market for a large-scale installation.Herein,we report a novel low-cost and biodegradable lead sequestration layer with high compatibility for up-scalable encapsulation of PSCs.Through a precisely designed cross-linking reaction of chemical agents,the as-made biodegradable chitosan composite film shows enhanced mechanical strength,chemical stability,and lead adsorption capacity.The designed encapsulation strategy reduces over 99.99% lead leakage to <2 ppb under varied simulations of weather conditions(hail,rain,or flood),which meet the safe level of drinking water set by the US Environmental Protection Agency(EPA).Moreover,the PSC efficiency is improved from 21.91% to22.82% due to the improved light absorption from the printed biodegradable lead absorption film.Finally,we present a prototype process of accumulation and recycling of lead compounds in PSCs derbies via the biodegradation process.Based on the low-cost biodegradable lead sequestration film,this environmental-friendly encapsulation strategy could address the lead leakage issue for further commercialization of PSCs.

Interface passivation engineering for hybrid perovskite solar cells

The allure of high efficiency and low-temperature solution-processed organic-inorganic hybrid perovskite solar cells(PSCs)are inspiring scientists to seek for its commercialization.Interface passivation engineering has become an effective way to further enhance the efficiency and stability of PSCs by defect passivation,reduces the charge recombination and ion migration initiation and hysteresis control,etc.Herein,we have summarized the effects and recent research progress of interface passivation engineering in PSCs.Interface passivation layers can be realized by using the solution and/or vacuum evaporation processes which are very adaptable to varied materials with different properties and fabrication processes for enhanced photovoltaic performance and stability.

In-situ monitored chemical bath deposition of planar NiO x layer for inverted perovskite solar cell with enhanced efficiency

As a convenient,low-cost and up-scalable solution route,chemical bath deposition(CBD)has exhibited impressive advantages in fabricating electron transporting materials like SnO_(2),achieving record efficien-cies for regular n-i-p perovskite solar cells(PSCs).However,for the hysteresis-free and potentially more stable inverted p-i-n PSCs,CBD processing is rarely studied to improve the device performance.In this work,we first present a CBD planar NiO x film as the efficient hole transport layer for the inverted per-ovskite solar cells(IPSCs).The morphologies and semiconducting properties of the NiO x film can be ad-justed by varying the concentration of[Ni(H 2 O)x(NH 3)6-x]2+cation via in-situ monitoring of the CBD re-action process.The characterizations of ultraviolet photoelectron spectroscopy,transient absorption spec-troscopy,time-resolved photoluminescence suggest that the CBD planar NiO x film possesses enhanced conductivity and aligned energy band levels with perovskite,which benefits for the charge transport in the IPSCs.The devices based on planar NiO x at 50°C and low nickel precursor concentration achieved an enhanced efficiency from 16.14%to 18.17%.This work established an efficient CBD route to fabricate planar NiO x film for PSCs and paved the way for high performance PSCs with CBD-prepared hole transporting materials.