Supporting Information. Single-Layer Halide Perovskite Light-Emitting. Diodes with Sub-Bandgap Turn-on Voltage and

Transcription

1 Supporting Information Single-Layer Halide Perovskite Light-Emitting Diodes with Sub-Bandgap Turn-on Voltage and High Brightness Junqiang Li, Xin Shan, Sri Ganesh R. Bade, Thomas Geske,, Qinglong Jiang, Xin Yang, and Zhibin Yu *,, Department of Industrial and Manufacturing Engineering, High Performance Materials Institute, Florida State University, Tallahassee FL 32310, USA Materials Science and Engineering, Florida State University, Tallahassee FL 32306, USA S1

2 Figure S1. Top-view SEM images of film with a) CsPbBr3:PEO = 100:10 and c)100:100. Crosssectional tilted-view images of b) 100:10 and d) 100:100 samples Figure S2. Top-view SEM images of film with a) CsPbBr3:PVP = 100:5 and c)100:30. Crosssectional tilted-view images of b) 100:5 and d) 100:30 samples S2

3 Figure S3. Chemical structure of the PVP polymer Power efficiency (lm W -1 ) Ref. 19 Ref. 15 Ref. 16 Ref. 22 Ref. 13 Ref. 20 Ref. 23 Ref. 17 Ref. 11 Ref. 27 Ref. 12 MA-Pero Ref. 18 Cs-Pero k 10k 100k 1M Maximum luminance (cd m -2 ) This work Figure S4. Comparison of maximum luminance and power efficiency of our Cs-Pero LEDs with reported Cs-Pero and MA-Pero green LEDs. S3

4 4 2 light light Current (na) Time (min) Figure S5. Photocurrent response of an un-biased pero-led device. Figure S6. Band diagram schematic at the cathode/composite interface for the ITO/CsPbBr3- polymer composite/in-ga device with (solid) and without (dot-dashed) doping effect. e is elementary charge, V represents the voltage drop across the cathode/cspbbr3 interface, and EF is the quasi Fermi level of CsPbBr3 in the composite film. S4

5 Figure S7. Stress test of pero-leds with the 100:50:5 emissive layer at a) 3.5 V and b) 2.7 V bias in a nitrogen filled dry box. Figure S8. Photo of one 100:50:5 device at 4 V under sunlight. The devices were illuminated in ambient air (30 o C and 60% relative humidity). S5

6 Figure S9. Multiple scanning cycles of J-V (a) and L-V (b) tests of one Pero-LED from 0 to 4 V Figure S10. Multiple scanning cycles of J-V (a) and L-V (b) tests of one Pero-LED from 0 to 6 V, and a lit device at 3 V after the 4 th scan cycle (c). Figure S11. A photo of two LED devices after -10 V biasing. The dark regions represent the active area of the LEDs. S6

7 Table S1. Summary of performances for 8 pero-leds in a single batch with 100:50:5 composite emissive layer. Device No. Turn-on voltage (V) Maximum current efficiency (cd A -1 ) Corresponding Voltage (V) Corresponding luminance (cd m -2 ) EQE (%) Maximum power efficacy (lm W -1 ) , , , , , , , , Si photodiode calibration: Figure S12 A schematic of LED measurement setup Spectral radiance I(λ) and luminance L are linked by L = K m I(λ) V(λ)dλ (1) where Km = 683 lm W -1 is the maximum spectral luminous efficacy of radiation for photopic vision and V(λ) is the spectral responsivity of a human eye. When illuminated by the light source, the short circuit current of the photodiode I SC = A E(λ) R(λ)dλ (2) Where A is the area of the aperture, E(λ) is the spectral irradiance, and R(λ) is the known spectral responsivity of the photodiode. when d²>>s (S is the area of light source, d is the distance between photodiode and light source), S7

8 we have E(λ) = I(λ) S/d 2 (3) From (1)-(3), we can obtain L = d2 K m I(λ)V(λ)dλ I SC AS I(λ)R(λ)dλ (4) For Pero-LED with same emission profile (the normalized EL spectra have identical shape), we have I(λ) = k I0(λ), where standard I0(λ) can be the spectral radiance at an arbitrary testing condition and k is just a coefficient. When d is fixed, we can get L = α I SC S (5) Where α is a constant that can be determined by using a reference sample with known emission profile and luminance. We used a cellphone screen as a reference light source. The screen was set to green emission using a Screen Test App, and the luminance and emission spectrum were measured by a PR-655 spectroradiometer. A shadow mask with a 2 mm diameter hole was adhered onto the cellphone screen, and used as a reference light source for the silicon photodiode calibration. We have also used PR-655 to directly measure a working device, and obtained a luminance of 176,000 cd m -2 at 4 V. Such a result is in good agreement with the J-V-L measurement using the calibrated silicon photodiode. It is worth mentioning the PR-655 has a measurement limit of ~30,000 cd m -2 for green color LEDs. We used neutral density filters (3% transparency) to obtain the above 176,000 cd m -2. S8