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Supplementary Materials

A high-efficiency bioinspired interfacial evaporation driven

nanogenerator

Zhuangzhi Sun1,2,*, Zhaoxin Li1,*, Chuanlong Han1, Mingxing Jing1, HaipengYu2,*, Zuankai

Wang3,*

1 Province Key Laboratory of Forestry Intelligent Equipment Engineering, College of Mechanical

and Electrical Engineering, Northeast Forestry University, Harbin 150000, People’s Republic of

China.

2 Key Laboratory of Bio-based Material Science & Technology, Ministry of Education, Northeast

Forestry University, Harbin 150000, People’s Republic of China.

3 Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong

Kong, People’s Republic of China.

E-mail: sunzhuangzhi@nefu.edu.cn; 2014211213@nefu.edu.cn; yuhaipeng20000@aliyun.com;

zuanwang@cityu.edu.hk

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Brief description of what this file includes:

Supplementary Fig. 1. Preparation process of the BLT-IENG.

Supplementary Fig. 2. Moth eye structure and evaporation properties of the BLT-IENG.

Supplementary Fig. 3. Evaporation properties of different moth eye structure.

Supplementary Fig. 4. Evaporation properties of bionic moth eye structure with different

proportion.

Supplementary Fig. 5. Composition and element content of the BLT-IENG.

Supplementary Fig. 6. Power generation performance of Control 1 (α-cellulose hydrogel with

TiO2, SiO2 and TiNx) and α-cellulose hydrogel.

Supplementary Fig. 7. Water evaporation properties of BLT-IENG at a 1.0 kW·m-2.

Supplementary Fig. 8. Optimal analysis of bionic moth eye surface with Cs4PbBr6 type

perovskite.

Supplementary Fig. 9. Surface temperature infrared photos of different BLT-IENGs recorded via

IR camera.

Supplementary Fig. 10. Thermal insulation and water absorption capacity of the BLT-IENG.

Supplementary Fig. 11. Interfacial evaporation coupling enhancement mechanism of the

BLT-IENG.

Supplementary Fig. 12. Water purification capacity and power generation performance of the

BLT-IENG.

Supplementary Fig. 13. The evaporation test of BLT-IENGs outdoor.

Supplementary Fig. 14. The collection device illustration for ocean power generation and fresh

water production.

Supplementary Note 1. Water evaporation rate measurement.

Supplementary Note 2. Evaluation of the energy conversion efficiency (η).

Supplementary Note 3. Analysis of light absorption characteristics of the BLT-IENG.

Supplementary Note 4. Thermal conductivity measurement.

Supplementary Note 5. Relationship of electron velocity v1 and solution flow rate v0.

Supplementary Note 6. Relationships of the electron velocity v1 with theshort-circuit current (ISC)

and the open-circuit voltage (VOC).

References.

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Supplementary Figure 1. Preparation process of the BLT-IENG.

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Supplementary Figure 2. Moth eye structure and evaporation properties of the BLT-IENG.

a Photograph of a bean hawk moth. b SEM image of the hexagonal structure inside the moth eye.

c Experimental sample model with the BLC layer. d SEM image of Cs4PbBr6-type perovskite

particles on the BLC layer. g Energy conversion efficiency improvement principle of BLT-IENG

by changing the form of water. f Principle of photothermal conversion and transfer of particles in

BLT-IENG (take TiO2 as example).

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Supplementary Figure 3. Evaporation properties of different moth eye structure. a

Evaporation of bionic Moth eye with different shapes. b Temperature changes on the surface of

biomimetic Moth eye with different shapes recorded by infrared camera under 1.0 kW·m-2 light

intensity. c Temperature on the surface of bionic Moth eye with different shape. Structure a: the

bionic Moth eye structure with low concave distribution density. Structure b: the bionic Moth eye

with concave distribution and medium density. Structure c: the bionic Moth eye with high concave

distribution density. Structure d: the bionic Moth eye with a convex distribution density and a

small size shape. Structure e: the bionic Moth eye with convex distribution density and large size

shape. Structure f: the concave-convex shape bionic Moth eye with a high distribution density and

a small size shape.

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Supplementary Figure 4. Evaporation properties of bionic moth eye structures with

different proportions. a Unit area evaporation of bionic Moth eye with different proportions. b

Temperature changes on the surface of bionic Moth eye with different proportions recorded by the

IR camera under the light intensity of 1.0 Kw·m-2. c The surface temperatures of bionic Moth eye

different proportions.

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Supplementary Figure 5. Composition and element content of BLT-IENG. a Contrast. b

BLT-IENG with Cs4PbBr6 surface. c the BLT-IENG with BLC-layer.

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Supplementary Figure 6. Power generation performance of Control 1 (α-cellulose hydrogel

with TiO2, SiO2 and TiNx) and α-cellulose hydrogel. a The open-circuit voltage of the Control

1 induced by water evaporation. b The short-circuit current of the Control 1 induced by water

evaporation. c The open-circuit voltage of α-cellulose hydrogel induced by water evaporation. d

The short-circuit current of α-cellulose hydrogel induced by water evaporation

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Supplementary Figure 7. Water evaporation properties of BLT-IENG at a 1.0 kW·m-2. a The

water evaporation rate of BLT-IENG and other solar-driven evaporators. b Comparison of energy

conversion rates between BLT-IENG with BLC-layer and other evaporators

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Supplementary Figure 8. Optimal analysis of bionic moth eye surface with Cs4PbBr6 type

perovskite. a Light absorption efficiency of bionic Moth eye surface with different types of

perovskite and doping qualities at the wavelength range of 200 nm-900 nm. b Theoretical model

of the Moth eye structure. Λ is the period of Moth eye structure. h is the depth of Moth eye

structure. d is the bottom diameter of Moth eye structure. c Comparison of light absorption

efficiency between BLT-IENG with BLC-layer and other evaporators. d Comparison of the

average difference between BLT-IENG with BLC-layer and other evaporators at the stable stage of

light absorption.

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Supplementary Figure 9. Surface temperature infrared photos of different BLT-IENGs

recorded via IR camera.

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Supplementary Figure 10. Thermal insulation and water absorption capacity of the

BLT-IENG. a Thermal insulating principle of the ITW-layer. b Comparison of the surface

temperature of ITW-layer heated with different components after standing at 28 ℃. c Water

content ratios of the ITW-layer with different doping components in saturated state.

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Supplementary Fig. 11. Interfacial evaporation coupling enhancement mechanism of the

BLT-IENG. a Energy conversion efficiency improvement principle of BLT-IENG by changing

the form of water. b Principle of photothermal conversion and transfer of particles in BLT-IENG

(take TiO2 as example).

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Supplementary Figure 12. Water purification capacity and power generation performance

of the BLT-IENG. a Salinity before and after water purification. Sea water with an average

salinity of ∼1 wt % is collected from the Bohai Sea, China. b Current and voltage generated via

the BLT-IENG connected to a variable external load.

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Supplementary Figure 13. The evaporation test of BLT-IENGs outdoor. a Actual water

evaporation device of the BLT-IENG. b The evaporation test's condition of the BLT-IENGs. c

Mass loss of the BLT-IENGs under the normal light test condition. d The quality loss of

BLT-IENGs changes over time under the sunlight test condition. e Comparison of mass loss of

BLT-IENG with BLC-layer over time under the simulated condition and the actual sunlight. f The

mass change of the BLT-IENGs before and after water evaporation.

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Supplementary Figure 14. The collection device illustration for ocean power generation and

fresh water production.

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Supplementary Note 1. Water evaporation rate measurement

The water evaporation rate (E.R.) is given by the following equation

. . 10000m

E Rst

(S1)

where m is the mass reduction unit (kg), s is the upper surface area unit (cm2), and t is the

evaporation time (h).

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Supplementary Note 2. Evaluation of the energy conversion efficiency (η)

. . lv

opt i

E R h

C q

(S2)

where E.R. is the evaporation rate, hlv denotes the total enthalpy of liquid-vapor phase change, Copt

stands for the optical concentration, and qi is solar irradiation (1kW·m-2).

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Supplementary Note 3. Analysis of light absorption characteristics of the BLT-IENG

The light absorption efficiency with Cs4PbBr6 is significantly improved as shown in

Supplementary Fig. 9a. The reason is that Cs4PbBr6 has microscopic Moth eye structure, which

can reflect light multiple times and absorb fluorescence. Meanwhile, due to three-dimensional

structure of bionic Moth eye, the area exposed to light has been greatly enhanced. Therefore,

cooperating with bionic Moth eye to reduce light reflectivity, the light absorption efficiency of

BLT-IENG with BLC-layer has been greatly improved which is significantly higher than other

evaporators as shown in Supplementary Fig. 9c. Moreover, the electrospinning layer on its surface

can effectively smooth the unstable light absorption of the bionic Moth eye structure which makes

BLT-IENG with BLC-layer have the lower average difference in light absorption efficiency than

other solar evaporators (Supplementary Fig. 9d). Also, as an intermediate for light absorption, the

electrospinning layer can effectively solve the enhanced reflection effect of TiO2 and other

particles on the surface of BLT-IENG. Above all these, the energy conversion efficiency of the

BLT-IENG with the BLC-layer is higher than that of other solar evaporators as shown in

Supplementary Fig. 7b.

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Supplementary Note 4. Thermal conductivity measurement

The thermal conductivity of sample q" is given by the following equation

"dT

q Kdx

(S3)

where K is the thermal conductivity of glass, dT refers to temperature difference and dx is the

distance difference.

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Supplementary Note 5. Relationship of electron velocity v1 and solution flow rate v0.

0

1 ln2

B

C C

vEk Tv

L v

(S4)

2 2

exp CBC

C B

a Lk Tv

aL Ek T

(S5)

where μ is the electron migration rate. L, a and E are the length, thickness and elastic modulus of

the model slider, respectively. kB is the Boltzmann constant. v0 is the solution flow rate. v1 is the

electron velocity. α is the linear factor in the Newtonian fluid model (v=αv0). β is the

pre-exponential factor for calculating the activation energy required for slippage (Arrhenius

equation). σC is the critical elastic deformation tension.

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Supplementary Note 6. Relationships of the electron velocity v1 with short-circuit current

(ISC) and open-circuit voltage (VOC).

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1SC eI ren v

(S6)

0 12OC eV R ren v (S7)

where κ is the constant related to the interaction between ions and carriers, r is the radius of

MWNTs, e is the electronic charge, ne is the carrier concentration in MWNTs and R0 is the

resistance of MWNTs.

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