1HNMR (500MHZ, CDCl3, δ): 7.31-7.34 (m, 1H), 7.28-7.29 (m, 1H), 7.10-7.19 (m, 2H), 6.82-6.84

(d, 1H), 2.95 (t, 2H), 1.87 (m, 2H), 1.49-1.59 (m, 6H), 1.12 (t, 3H). 13CNMR: 145.40, 138.21,

135.01, 127.84, 124.90, 123.80, 123.53, 123.11, 31.87, 31.83, 30.39, 29.08, 22.90, 14.40.

1HNMR (500MHZ, CDCl3, δ): 7.31 (d, 1H), 7.13 (d, 1H), 7.07 (d, 1H), 6.75 (d, 1H), 2.87 (t, 2H),

1.65-1.80 (m, 10H), 1.40-1.49 (m, 14H), 1.21 (t, 4H), 1.01 (m, 10H). 13CNMR: 144.95. 144.44,

136.07, 135.67, 135.13, 124.73, 124.25, 123.10, 31.71, 31.70, 30.27, 29.15, 29.07, 28.98, 28.89,

27.62, 27.39, 27.16, 22.72, 14.22, 13.80, 12.34, 12.28, 10.94, 10.92, 9.57.

Electronic Supplementary Material (ESI) for Materials Chemistry Frontiers.This journal is © the Partner Organisations 2018

1HNMR (500MHZ, CDCl3, δ): 6.97 (s, 2H). 13CNMR: 132.99, 129.54, 114.84, 112.21.

BT-BTH

1HNMR (500MHZ, CDCl3, δ): 7.36 (s, 2H), 7.10 (d, 2H), 7.01 (m, 4H), 6.94 (d, 2H), 6.87 (m, 4H),

6.70 (d, 2H), 6.61 (d, 2H), 2.72-2.82 (m, 8H), 1.61-1.71 (m, 12H), 1.28-1.33 (m, 20H), 0.85-0.92 (m,

12H). 13CNMR:145.95, 145.49, 138.99, 138.04, 137.70, 136.55, 136.07, 135.30, 134.31, 130.96,

126.17, 125.10, 124.93, 124.83, 124.73, 123.65, 123.60, 123.47, 123.24, 123.19, 31.62, 30.19, 29.76,

28.83, 22.7, 14.14.

Fig. S1. Synthesis routes of BT-BTH and 1H NMR, 13C NMR spectra.

10 20 30 40 50 60 70

PbBr2 CsBr

Inte

nsity

(a.u

.)

2θ

CsPbBr3

FTO

Fig. S2. The X-ray diffraction (XRD) pattern of CsPbBr3 film in FTO glass.

4000 3500 3000 2500 2000 1500 1000 5000

20

40

60

80

100

Tran

smitt

ance

/ a.

u.

Wavenumber / cm-1

PEDOT

785

1086

843

1435

1541

4000 3500 3000 2500 2000 1500 1000 500

0

20

40

60

80

100

Tran

smitt

ance

/ a.

u.

Wavenumber / cm-1

PPy

1034

1454

1543

4000 3500 3000 2500 2000 1500 1000 500

0

20

40

60

80

100

Tran

smitt

ance

/ a.

u.

Wavenumber / cm-1

PANi

1550

1473

1288

1110

3397

4000 3500 3000 2500 2000 1500 1000 500

0

20

40

60

80

100

Tran

smitt

ance

/ a.

u.

Wavenumber / cm-1

BT-BTH

1027

785

1722

2931

Fig. S3. FTIR spectra of BT-BTH, PEDOT, PPy and PANi.

FTIR absorption spectrum for the polymers and small-molecule BT-BTH are shown in Fig. S3.

The bands around 1435 cm-1 are typical of the C=C symmetric stretching vibrations of thiophene

ring and the appearance of peaks at around 785 cm-1 is C–H out of plane vibration. In addition to, the

presence of characteristic absorption bands at 1555 cm-1 (C=C stretching vibration of the quinoid

ring), 1476 cm-1 (stretching vibration of C=C of the benzenoid ring) and 1288 cm-1 (C-N stretching

vibration). The bands in the range of 3000-3500 cm-1 correspond to secondary amine stretching (N-H)

vibrations.

Fig. S4. Cross-sectional SEM image of a PSC device.

Fig. S4 shows the cross-sectional SEM image of a PSC device with FTO/TiO2/CsPbBr3/HTM/carbon structure.

Fig. S5. The magnified SEM image of a total PSC device.

The thicknesses of carbon electrode is about 15 um.

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.40

2

4

6

8

10

Curr

ent d

esity

(mA/

cm2 )

Voltage (V)

1mg 3mg 5mg 10mg

Fig. S6. Photo J-V curves of inorganic CsPbBr3 PSCs by coating BT-BTH solutions with different

concentrations.

Fig. S6 shows the J-V curves of inorganic CsPbBr3 PSCs. It can be concluded the device has

excellent performance by coating the BT-BTH solution with a concentration of 3 mg/mL.

Fig. S7. The cross-sectional images of FTO/BT-BTH, and the concentrations of BT-BTH solutions

are (a) 1 mg/mL, (b) 3 mg/mL, (c) 5 mg/mL, (d) 10 mg/mL,.

The cross-sectional views of BT-BTH films by coating the solutions with concentrations of 1, 3,

5 and 10 mg/mL, as shown in Fig. S7, suggesting average thicknesses of 50, 70, 90 and 120 nm,

respectively.

a b c d

7

8

9

10

PCE

(%)

BT-BTH PEDOT PPy PANi

a

0

2

4

6

8

10

0 20 40 60 80 100

PANi

PCE

(%)

PEDOT PPy

Times (s)

BT-BTH

b

Pristine

Fig. S8. (a) The PCE distribution of 10 random devices for each device with different HTMs. (b)

Steady-state power outputs at the maximum power point for HTM-free and HTM tailored PSCs.

0.0 0.5 1.0 1.5 2.0-0.0005

-0.0004

-0.0003

-0.0002

-0.0001

0.0000

0.0001

HOMO = -(0.8+4.4) = -5.2 eV

Cur

rent

(A)

Voltage (V)

0.8

PANi

0.0 0.5 1.0 1.5 2.0 2.5-0.0014

-0.0012

-0.0010

-0.0008

-0.0006

-0.0004

-0.0002

0.0000

0.0002

0.4 0.6 0.8 1.0 1.2 1.4

Cur

rent

(mA

)

Voltage (V)

0.63 eV

HOMO = -(0.83+4.4) = -5.23 eV

Cur

rent

(mA

)

Voltage (V)

PPy

0.0 0.5 1.0 1.5

-0.00015

-0.00010

-0.00005

0.00000

0.00005

HOMO = -(1.04+4.4) = -5.44 eV

Cur

rent

(mA

)

Voltage (V)

1.04 eV

BT-BTH

0.4 0.6 0.8 1.0 1.2 1.4

-0.000006

-0.000004

-0.000002

0.000000

0.000002

HOMO = -(0.87+4.4) = -5.27 eV

Cur

rent

(mA

)

Voltage (V)

0.87eV

PEDOT

Fig. S9. CV curves of different HTMs.

500 510 520 530 540 550 560 570 580

PL in

tens

ity (a

.u.)

Wavelength (nm)

BT-BTH PEDOT PPy PANi Pristine

Fig. S10. The steady-state PL spectra of pristine device and BT-BTH, PEDOT, PPy, PANi based

devices.

0.01 0.1 10.01

0.1

1

10

100

Voltage (V)

Curr

ent d

ensit

y (m

A cm

-2)

BT-BTH PEDOT PPy PANi Pristine

VTFL

Fig. S11. The space-charge limited current (SCLC) characterizations of pristine and coated with

different HTM layers.

The holes mobility of the cesium lead bromide films is further studied using a space-charge

limited current (SCLC) model. Figure S8 shows SCLC curves of five devices. The trap density can

be obtained according to VTFL = entL2/2εε0, VTFL is trap-filled limit voltage. The corresponding VTFL

values of BT-BTH, PEDOT, PPy, PANi, Pristine device are 0.126 V, 0.136 V, 0.169 V, 0.187 V,

0.215 V, respectively. Therefore, BT-BTH device has the highest device according to the

proportional relation between nt and VTFL.