Room-Temperature Processing of Inorganic Perovskite Films to Enable Flexible Solar Cells

Inorganic lead halide perovskite materials have attracted great attention recently due to their potential for greater thermal stability compared to hybrid organic perovskites. However, the high processing temperature to convert from the non-perovskite phase to cubic perovskite phase in many of these systems has limited their application in flexible optoelectronic devices. Here, we report a room temperature processed inorganic PSC based on CsPbI2Br as the light harvesting layer. By combing this composition with key precursor solvents, we show that the inorganic perovskite film can be prepared by the vacuum-assist method under room temperature conditions in air. Unencapsulated devices achieved the power conversion efficiency up to 8.67% when measured under 1-sun irradiation. Exploiting this room temperature process, flexible inorganic PSCs based on an inorganic metal halide perovskite material is demonstrated.Comment: 23 pages, 4 figures, and supplemental informatio

Chemical studies of the passivation of GaAs surface recombination using sulfides and thiols

Steady-state photoluminescence, time-resolved photoluminescence, and x-ray photoelectron spectroscopy have been used to study the electrical and chemical properties of GaAs surfaces exposed to inorganic and organic sulfur donors. Despite a wide variation in S2–(aq) concentration, variation of the pH of aqueous HS–solutions had a small effect on the steady-state n-type GaAs photoluminescence intensity, with surfaces exposed to pH=8, 0.1-M HS–(aq) solutions displaying comparable luminescence intensity relative to those treated with pH=14, 1.0-M Na2S·9H2O(aq). Organic thiols (R-SH, where R=–CH2CH2SH or –C6H4Cl) dissolved in nonaqueous solvents were found to effect increases in steady-state luminescence yields and in time-resolved luminescence decay lifetimes of (100)-oriented GaAs. X-ray photoelectron spectroscopy showed that exposure of GaAs surfaces to these organic systems yielded thiols bound to the GaAs surface, but such exposure did not remove excess elemental As and did not form a detectable As2S3 overlayer on the GaAs. These results imply that complete removal of As0 or formation of monolayers of As2S3 is not necessary to effect a reduction in the recombination rate at etched GaAs surfaces. Other compounds that do not contain sulfur but that are strong Lewis bases, such as methoxide ion, also improved the GaAs steady-state photoluminescence intensity. These results demonstrate that a general class of electron-donating reagents can be used to reduce nonradiative recombination at GaAs surfaces, and also imply that prior models focusing on the formation of monolayer coverages of As2S3 and Ga2S3 are not adequate to describe the passivating behavior of this class of reagents. The time-resolved, high level injection experiments clearly demonstrate that a shift in the equilibrium surface Fermi-level energy is not sufficient to explain the luminescence intensity changes, and confirm that HS– and thiol-based reagents induce substantial reductions in the surface recombination velocity through a change in the GaAs surface state recombination rate

Pasture deterioration trial

Trial 89NA61 Location: Duranillin In this site we would expect a very large response (40 to 50% ) to phosphorus. History: The site was chosen because of the patchy and poor pasture production. The poor areas tend to have more suckling clover than the good areas. The pasture was legume dominant. Treatments were applied on April 16, 1989

New block Badgingarra RS late time of seeding.

Trial 89BA33, Location: Badgingarra Based on a 1.5 t/ha potential yield, the strategic treatment was planned to be 120 kg urea/ha 4WAS. However, the crop was poorly established and so NH4NO3 was used in the hope of getting better tillering than would be possible with the slower release urea source. Gambling on equal dollars to urea for 2/3 N, but believe that twice as effective. DAP was used to place nitrogen with the seed in case there was no rain of significance after seeding. This nitrogen (only 5 kg/ha) was probably lost with the rains of 20-28/7/89 (50 mm). Urea (60 kg/ha) was applied at 4WAS with the option to apply more later if yield potential warranted it. Trial 89BA32 1st Top Hand harvest 7/12/989 Trial 89BA32 2nd Top Hand harvest 7/12/89 Trial 89BA32 Tiller Analysis About 20 plants per replicate for each of four replicates were described. The results are expressed per hundred plants. There were on average, about one hundred plants per metre squared

General Phosphorus Trials

The trial programme of past years was considerably reduced in size because of the absence of J.W. Bowden (Research Officer). Further, extensive drought conditions in the W.A. agricultural areas wiped out several trials. INDEX Super x stocking rate trial 66M30. Maintenance P x S trials 65Al, 65C5, 65N5, 69WH15. Residual Value of Phosphorus 75LG26, 77NA4, 78BA7, 79N05, 79JE8 & 9. Times and Methods of Application 80M7, 8OM6, 80WH9, 80MO7

Sources of phosphorus trials. Miscellaneous trials.

I Sources of phosphorus work. Pasture trials - 77MT1 - New land (1977) continuous pasture trial, gravel. 80BA6 - Ley 1984. Serradella weeds and lupin regrowth, sand. 84N069 - New land (1984) pasture, gravel. Crop trials - 76WH9 - New land (1976) run down on one dressing of P W.L.S. 76WH10 - Young land Topdressed annually, biennially and once off. 76WH14 - Old land Topdressed anually and biennially. 76N4 - New land (1976) Topdressed annually biennially and once off, gravel. 84M63 - New land (1984) Once off dressing. Trials not sampled - 77WH2 - Old land Sources trial 77MT2 - Old land Sources trial II Miscellaneous trials. Maintenance P x S trials 65C5 and 65A1. Residual value of Phosphorus 78BA7. Grazing trial, Wooroloo 83PE35. Cultivation of Phosphorus availability 83BU1, 3 and 4 84MT7. Rates and times of nitrogen 84WH45. Ripping Trials - Residual effects 82WH2, 35 83WH28 and 31. Coarse organic matter for nitrogen: second crop effects 82N041, N17 and LG5

Summary of 1974 Phosphorus and sulphur group

Stocking x Super Rate - Merredin - 66M30. Twitcham - 62MB9. Kojonup - 68BR7. Maintenance P x S Trials - I. Residual Value - 66N07 and 66ME3. II. Wheatbelt Rate Trials - 67N011, 66LG1, 68LG1, 67NO5, 6NA3, 67GE2, 66M06 and 67M01. III. Wheatbelt Research Stations and Farmers- 65C5, 65A1, 65N5,69WH15 and 66N09. IV. Higher Rainfall Area Trials - 68B1, 68BU2, 68BR5,68AL3, 69E6, 69AL2 and 69AL3. Miscellaneous Trials - 74GE2, 74GE4, 74GE5,74JE3, 74LG4, 74M06, 74M07, 74TS3, 74NA3 74NA4, 74M07, 74TS4