Electronic Grade and Flexible Semiconductor Film … Electronic Grade and Flexible Semiconductor Film Employing Oriented Attachment of Colloidal Ligand-Free PbS and PbSe Nanocrystals

1  

Electronic Grade and Flexible Semiconductor Film Employing

Oriented Attachment of Colloidal Ligand-Free PbS and PbSe

Nanocrystals at Room Temperature

G. Shiva Shanker,a Abhishek Swarnkar, a Arindom Chatterjee,b S. Chakraborty,c

Manabjyoti Phukan,a Naziya Parveen,a Kanishka Biswas,b Angshuman Naga,*

aDepartment of Chemistry, Indian Institute of Science Education and Research (IISER), Pune,

411008, India.

b New Chemistry Unit and Sheikh Saqr Laboratory, Jawaharlal Nehru Centre for Advanced

Scientific Research (JNCASR), Jakkur P.O., Bangalore 560 064, India

c Centre for Advanced Materials, Indian Association for the Cultivation of Science, Kolkata-

700032, India

*Corresponding author’s e-mail: [email protected]

Electronic Supplementary Information (ESI) 

Electronic Supplementary Material (ESI) for Nanoscale.This journal is © The Royal Society of Chemistry 2015

2  

Materials:

Lead (II) nitrate (sigma- aldrich, purity ≥ 99%), formamide(FA, fluka analytical , purity 99.0%),

ammonium sulphide (40 - 48 wt % solution in water, aldrich ), sodium selenide (alfa aesar,

purity 99.8%), acetonitrile (dry, S D fine chem Ltd ), n-butanol (Analytical reagent, Rankem),

ethanol (99.9% AR, S D fine chem Ltd), sodium chloride (AR, Rankem), colloidal silver liquid

(TED PELLA, INC), polyethylene terephthalate (PET substrate, aldrich). All the chemicals were

used without any further purification.

Figure S1: Infra-red absorption spectrum of PbS nanocrystal (NC) precipitate. 

Figure S2: Photoluminescence (PL) spectra for same sample of ligand-free PbS nanocrystals (NCs) in FA at different time after stopping the reaction immediately after injecting S2- solution in Pb2+ solution.

1.4 1.6 1.8 2.0 2.2 2.40.0

0.2

0.4

0.6

0.8

1.0

No

rmal

ize

Inte

nsi

ty

Energy (eV)

1 min 5 min 15 min

PbS NCs

0.30 0.35 0.40 0.45 0.50

PbS NC precipitate

Energy (eV)

Ab

sorb

ance

3  

Figure S3: Surface profilometry of three different PbS films showing the control over film

thickness in the range of 1 to 15 m.

Figure S4: FESEM image of PbS NC film on glass substrate processed at 25 oC.

0 1 2 3 4 5 6 7

0

1

2

3

Pro

file

hei

ght

(m

)

Traced Distance (mm)

PbS NC film

0 1 2 3 4 5 6 7 8

0

2

4

6

8

10

Pro

file

hei

ght

(m

)

Traced Distance (mm)

PbS NC film

0 1 2 3 4 5 6 7

0

5

10

15

20

Pro

file

hei

ght

(m

)

Traced Distance (mm)

PbS NC film

4  

Figure S5: Powder x-ray diffraction (XRD) patterns of PbS NC films processed at room temperature (RT) and 150 oC.

Figure S6: -potential of ligand-free colloidal PbSe NCs dispersed in FA. Open circles represents the experimental data and the solid line is a guide to eye.

20 30 40 50 60 70 80

Inte

nsi

ty (

a. u

.)

2(degree)

RT

150oC

PbS NCs

-150 -100 -50 0 50 100 150

Inte

nsi

ty (

a. u

)

- Potential (mV)

-Potential -44 mV

5  

Figure S7: HRTEM image of ligand-free PbSe NC precipitate.

Figure S8: Infra-red absorption spectrum of PbSe nanocrystal (NC) precipitate. 

0.25 0.30 0.35 0.40

PbSe NC precipitate

Energy (eV)

Ab

sorb

ance

6  

Figure S9: FESEM image of PbSe NC film on glass substrate processed at 25 oC.

Figure S10: Four-probe Current (I) vs voltage (V) plot for PbSe NC film on glass substrate after annealing at 150 oC. Electrical measurement was done at room temperature.

-10 -5 0 5 10-0.04

-0.02

0.00

0.02

0.04

Current ()

Vo

ltag

e (v

)

7  

Figure S11: Powder XRD pattern of PbSe NC film after annealing at 150 oC.

-1-11

1-11

200

11-1

-11-1

-200

20 30 40 50 60 70 80

Inte

nsi

ty (

a. u

)

2 (degree)

PbSe NCs

PbSe bluk reference