Direct indirect character of the band gap in methylammonium lead iodide perovskite

Transcription

1 Direct indirect chrcter of the nd gp in methylmmonium led iodide perovskite Eline M. Hutter 1, Mrí C. Gélvez-Rued 1, Ann Osherov 2, Vldimir Bulović 2, Ferdinnd C. Grozem 1, Smuel D. Strnks 2,3*, nd Tom J. Svenije 1* 1 Opto-electronic Mterils Section, Deprtment of Chemicl Engineering, Delft University of Technology, vn der Msweg 9, 2629 HZ Delft, The Netherlnds 2 Reserch Lortory of Electronics, Msschusetts Institute of Technology, 77 Msschusetts Avenue, Cmridge, MA 02139, U.S.A 3 Cvendish Lortory, JJ Thomson Avenue, Cmridge CB3 0HE, United Kingdom *e-mil: sds65@cm.c.uk *e-mil: T.J.Svenije@tudelft.nl NATURE MATERIALS 1

2 Supplementry Figure 1: Scnning Electron Microgrph of 250 nm thin CH 3NH 3PI 3 film spincoted from n cette-sed precursor solution. Supplementry Figure 2: X-ry diffrction (XRD) ptterns of CH 3NH 3PI 3 thin film deposited on oron-doped Si(100) sustrtes, recorded t 300 K (left) nd 120 K (right). The (110) reflections re mgnified in the inset. Supplementry Figure 3: Normlized photo-conductnce s function of time fter excittion t 2.0 ev (red) nd 1.7 ev (lck) t T = 300 K for n sored photon fluence of 1.1 x cm -2 () nd 1.6 x cm -2 () per pulse. Note tht this photon fluences re respectively one nd three orders of mgnitude higher thn for the trces shown in Figure 1 (min text). 2 NATURE MATERIALS

3 SUPPLEMENTARY INFORMATION Supplementry Figure 4: Excittion-dependent photo-conductnce for 2 x sored photons/cm 2 per pulse, which corresponds to chrge crrier density of 8 x cm -3. This is higher thn the fluence of 8 x 10 8 sored photons/cm 2 per pulse shown in Figure 1 in the min text. Supplementry Figure 5: Photo-conductnce s function of time fter excittion t 753 nm (1.65 ev) for different fluences of sored photons, where 8 x 10 8 sored photons/cm 2 per pulse corresponds to the dt presented in Figure 1 nd. The mximum height of the signls represents φσμ the product of genertion yield nd moility (sum of electrons nd holes). These results show tht the peking φσμ for exciting t 1.65 ev is even more pronounced t fluence of 2 x 10 8 sored photons/cm 2 (8 x chrge crriers cm -3 ) per pulse. At this density, the effective moility is in excess of 150 cm 2 /Vs. Supplementry Figure 6: Direct comprison etween the photo-conductnce ction spectr t 300 K (red, left xis) nd 120 K (lue, right xis). NATURE MATERIALS 3

4 Supplementry Figure 7: ) Mximum photo-conductnce s function of temperture upon cooling the CH 3NH 3PI 3 film, s presented in Figure 1e of the min text. The lck line shows the T -1.5 proportionlity of the moility, s reported y other groups. 1,2 ) Temperture-dependent moility mesured with pulse-rdiolysis TRMC (PR-TRMC) mesurements. Note tht the solute vlues otined with PR-TRMC mesurements () re lower thn those otined with photon-induced TRMC (). Considering tht moilities mesured with photon-induced TRMC () re similr to those otined with THz spectroscopy, 1 it seems unlikely tht using different frequencies chnges the mesured moility sustntilly. Insted, the reltively lower moility otined with the PR-TRMC mesurements could stem from n overestimtion of the numer of chrge crriers (see experimentl section). Nevertheless, this does not ffect the temperture-dependent moility trend. Supplementry Figure 8: ) (110) nd ) (220) reflections from the XRD ptterns otined t 140 K for cooling (green) nd heting (ornge) CH 3NH 3PI 3, suggesting co-existence of the orthorhomic nd tetrgonl phses. 4 NATURE MATERIALS

5 SUPPLEMENTARY INFORMATION Supplementry Figure 9: Frction of the initil chrge crrier concentrtion leding to free chrges s function of temperture for exciton inding energies of 5 mev () nd 16 mev () ccording to the Sh eqution: xx 2 1 xx = 1 3/2 nn (2ππππkk BBTT h 2 ) ee EE BB kk BB TT The initil chrge densities rnge from to cm -3. The chrge crrier densities in the TRMC experiments re on the order of cm -3, nd ~10 17 cm -3 for the (TR)PL mesurements. Supplementry Figure 10: Instrumentl response function for mthemticl short (< 4 ns) photoconductnce signl mesured with response time of 2 ns (red) nd 18 ns (lue). Supplementry Figure 11: Mximum emission wvelength s function of temperture for tetrgonl (red) nd orthorhomic (lue) CH 3NH 3PI 3. NATURE MATERIALS 5

6 160 K 180 K 220 K 260 K 300 K Second order recomintion rte (k 2) (cm 3 s -1 ) 1.0E E E E E-09 Trp-filling rte (k T) (cm 3 s -1 ) 3.0E E E E E-10 Trp-emptying rte (k R) (cm 3 s -1 ) 5.0E E E E E-11 Trp density N T (cm -3 ) 1.5E E E E E+15 Supplementry Figure 12: ) Experimentl temperture-dependent photo-conductnce, together with the fits (solid lines) otined y using the kinetic model detiled in Ref. 3. ) Kinetic prmeters otined from fitting the dt shown in (). c 160 K 180 K 260 K 300 K Second order recomintion rte (k 2) (cm 3 s -1 ) 2.1E E E E-10 Trp-filling rte (k T) (cm 3 s -1 ) 9.0E E E E-10 Trp-emptying rte (k R) (cm 3 s -1 ) 5.0E E E E-11 Trp density N T (cm -3 ) 4.0E E E E+16 Supplementry Figure 13: ) Temperture-dependent TRPL for CH 3NH 3PI 3 film prepred from PI 2. ) k 2 otined from fitting the dt from (). c) Kinetic prmeters otined from fitting the dt shown in (). 6 NATURE MATERIALS

7 SUPPLEMENTARY INFORMATION Supplementry Figure 14: Temperture-dependent photo-conductnce in meso-structured CH 3NH 3PI 3 prepred from PAc 2 for the orthorhomic () nd tetrgonl () phse. Supplementry Figure 15: Photo-conductnce t 300 K, 220 K nd 180 K in CH 3NH 3PI 3 film prepred from PI 2 for vrious incident photon fluences. NATURE MATERIALS 7

8 c d Supplementry Figure 16: Emission spectr t 180, 220 nd 300 K () nd 150, 120 nd 90 K (). TRPL decys recorded t the wvelengths corresponding to the emission peks centered t 742 nd 780 nm (90 K, c) nd 740 nm (120 K, d). Supplementry Figure 17: pulse-rdiolysis TRMC lifetimes for tetrgonl (160 to 293 K) nd orthorhomic (120 nd 130 K) CH 3NH 3PI 3. 8 NATURE MATERIALS

9 SUPPLEMENTARY INFORMATION Supplementry Figure 18: Asorption coefficient (cm -1 ) s function of excittion energy (see eq. 6 min text). Supplementry Figure 19: Light sorption profile s function of excittion energy, showing tht the homogeneity of the initil chrge distriution is not the origin of the pek t 1.7 ev since the penetrtion depth is similr to 1.8 nd 1.65 ev. PL (norm.) Asored photons 3x10 11 cm -2 3x10 12 cm -2 3x10 13 cm -2 3x10 14 cm Time (ms) Supplementry Figure 20: TRPL for excittion intensities rnging from 3x10 11 to 3x10 14 sored photons/cm 2 per pulse ( = 405 nm, repetition rte 0.5 MHz), corresponding to excittion densities of to cm -3. These excittion fluences cover the rnge from imoleculr recomintion t the lower fluences to the onset of Auger processes t the higher fluences. 4 References 1. Milot, R. L., Eperon, G. E., Snith, H. J., Johnston, M. B. & Herz, L. M. Temperture- Dependent Chrge-Crrier Dynmics in CH3NH3PI3 Perovskite Thin Films. Adv. Funct. NATURE MATERIALS 9

10 Mter. 25, (2015). 2. Krkus, M. et l. Phonon-Electron Scttering Limits Free Chrge Moility in Methylmmonium Led Iodide Perovskites. J. Phys. Chem. Lett. 6, (2015). 3. Hutter, E. M., Eperon, G. E., Strnks, S. D. & Svenije, T. J. Chrge Crriers in Plnr nd Meso-Structured Orgnic-Inorgnic Perovskites: Moilities, Lifetimes nd Concentrtions of Trp Sttes. J. Phys. Chem. Lett. 6, (2015). 4. Wehrenfennig, C., Eperon, G. E., Johnston, M. B., Snith, H. J. & Herz, L. M. High Chrge Crrier Moilities nd Lifetimes in Orgnoled Trihlide Perovskites. Adv. Mter. 26, (2014). 10 NATURE MATERIALS