Supplementary Information

Well-Ordered Monolayer Growth of Crown-Ether Ring Molecules onCu(111) in Ultra-High Vacuum: A STM, UPS, and DFT Study
Ryohei Nemoto1, Peter Krüger1,2, Ayu Novita Putri Hartini1, Takuya Hosokai3,
Masaki Horie4, Satoshi Kera1,5, and Toyo Kazu Yamada1,2*
1. Department of Materials Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan.
2. Molecular Chirality Research Center, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522,
Japan.
3. National Metrology Institute of Japan, National Institute of Advanced Industrial Science andTechnology, Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan.
4. Department of Chemical Engineering, National Tsing Hua University, 101, Sec. 2, Kuang-Fu Road,Hsinchu, 30013, Taiwan.
5. Institute for Molecular Science, Myodaiji, Okazaki 444-8585 Japan.

Author Information, Corresponding Author: Toyo Kazu Yamada,*E-mail: toyoyamada@faculty.chiba-u.jp

UHV-STM and UHV-UPS experimental setups and the molecule evaporator with QCM
rate check.

AFB

1Gas phaseThickness(Å)

15.5 ÅDDC power supplyESide view15.1 ÅC:H

12.6 Å

3:BrBulk

Top view
22:OOn Cu(111)3

1:C4030 @@@

201000@10203040Time (min)5060Figure S1 Experimental setups and Br-CR single molecule model in gas, in bulk, and on Cu(111)phases.
(A) Home-built UPS (LEED) setup. No.1 main, No.2 preparation, and No.3 Br-CR deposition chambers.
(B) Home-built low temperature UHV-STM setup. No.1 STM/cryostat, No.2 preparation, and No.3
deposition chambers. (C) Home built molecular evaporator. (D) Enlarged image of the evaporator in thebox in (C). Br-CR yellowish powders (~10 mg) were set inside the quartz crucible (~50 mm length). The
thermocouple monitored the crucible temperature. (E) QCM spectrum during the Br-CR evaporationfrom the crucible (distance from the crucible top is 110 mm). Used QCM parameters were z factor = 1,density = 1, tooling factor = 100%. Just above the crucible temperature higher than 84 oC, Br-CR startedto evaporate. In this study, we used the evaporation speed of 0.03 nm/min at 87.6 oC. (F) Br-CR single
molecule model in gas, in bulk crystal, and on Cu(111) phases. Top and side views. The single Br-CR
molecule consists of 20 carbon (black), 20 hydrogen (pink), 6 oxygen (red), and 4 bromide (brown)
atoms. In the side view, Br-Br distance is 1.26 nm, 1.51 nm, and 1.55 nm in gas, in bulk, and on Cu(111)phases, respectively.

UPS, STM atomic image, and STS surface state results obtained on the Cu(111) substrate.
AXe hν= 8.43 eV

Intensity [arb. units]

d band (Cu)

EB=182.1 eVsurfacestate-2[121] [112][211]0(dI/dV)/T [Arb. units]

B-1
Binding Energy [eV]C
dI/dV [nA/V]

-3

(00)

2.0
1.5
1.0

-1.0 -0.5 0.0 0.5 1.0

E-EF [eV]

Figure S2 Cu(111) substrate. (A) Angle-integrated UPS curve (XeI, 8.43 eV) and LEED spots obtainedon the Cu(111) surface. (B) Atomically-resolved STM image of fcc-Cu(111). Bright spots show Cu
atoms. (C) STS results of dI/dV curve (black dots), fitted tunneling probability function (exponentialbackground) curve (grey dots), and normalized (dI/dV)/T curve (blue dots). A surface state peak
appeared at −400 meV below the Fermi energy.

STM images of extra adsorbates on Cu(111).
One might be noted that, in Fig. 3A, most of the Cu substrate surface (see e.g. surroundings of the island in
Fig. 3F as well as terraces in Fig. S3C) was covered by very many adsorbates (diameter: ~1 nm, height: 50100 pm). These could be isolated single Br-CR molecules which did not contribute to grow the islands orimpurities included in the Br-CR powders, while we performed the Br-CR growth in UHV with a long (>1day) degas process. These adsorbates could be the reason why the Cu(111) surface state is UPS spectrum isstrongly suppressed by only the small coverage of Br-CR films (see Fig. 4C).

0.05 ML Br-CR on Cu(111)0.25 ML Br-CR on Cu(111)
0.6 nmA5 nm

2030x [nm]

32
10-1

spotz [Å]Cu(111)100.0 nmD4~240 pm

010 nm0.0 nmspots Δ ~ 100 pmz [Å]B543210-10.9 nm

C4050~240 pm

chainsCu(111)0204060x [nm]80100Figure S3 Extra adsorbates on the surface of 0.05 and 0.25 ML Br-CR on Cu(111). (A) STM
topographic image obtained on 0.05 ML Br-CR on Cu(111) (50×30 nm2, Vs = −0.7 V, It = 100 pA). In
the island, bright spots together with the stripe patterns are observed frequently between domains(domain boundaries). (B) Line profiles along the black, gray, and purple arrows in (A). (C) STM
topographic image obtained on 0.25 ML Br-CR on Cu(111) (100×60 nm2, Vs = −0.7 V, It = 100 pA).
Here, on the Cu(111), many chain structures were observed. (D) Line profiles along the black and grayarrows in (A).

Angle-resolved UPS results.

A He Iα 21.2 eV

BCu(111)

He IIα 40.8 eV Cu(111)35Angle(degree)

Angle(degree)

151050-5-10302520
15105-15-4-3-2-1

10-4

Binding Energy(eV)C-3-2-10

1

Binding Energy(eV)He Iα 21.2 eV 0.25 ML Br-CR / Cu(111)15Angle(degree)

1050-5-10-15-4-3-210-1Binding Energy(eV)

D He IIα 40.8 eV

0.25 ML Br-CR / Cu(111)35Angle(degree)

Angle(degree)

151050-5-1030252015105-15-4-3-2-10Binding Energy(eV)

1-4-3-2-101Binding Energy(eV)Figure S4 Angle-resolved UPS (±15 degrees).
(A) Cu(111), He Iα 21.2 eV. Right panel is an enlarged image of left panel. (B) Cu(111), He IIα 40.8
eV. Right panel was obtained angles from 5 to 35 degrees. (C) 0.25 ML Br-CR on Cu(111), He Iα 21.2
eV. (D) 0.25 ML Br-CR on Cu(111), He IIα 40.8 eV.

DFT calculations of free Br-CR molecules (see Fig. S5)
In order to better understand the energetics of Br-CR adsorption, we have studied the stiffness of the free
Br-CR molecule and the energy barrier between the gas phase (“bent”) and the crystal phase (“stepped”)
conformation. These calculations were done using the Gaussian09 software with 6-31(d) basis and B3LYP
potential. In the bent conformation, the calculated angle Ɵ between the two benzene rings is 112°. Fig.S5A
shows the energy as a function of Ɵ which was controlled by fixing the distance between the Br atoms. Theenergy cost of bending the molecule by ±35°, is only 0.1 eV, which demonstrates the high flexibility of BrCR. For making the molecule flat (θ = 180°) a moderate energy of 0.7 eV is required.
We have calculated the energy barrier between the bent and stepped conformation, see Figs. 5C and 5D. In
order to find a low energy path, the oxygen crown was first twisted by fixing the dihedral angle of CCOCgroups (blue atoms in conformations No.2-4) until the crown ring resembles that of the stepped configuration.
Then the whole molecule was bent by controlling a Br-O-Br angle (blue atoms in conformations No.5-10).
The calculated energy barrier height is 0.35 eV from the bent conformation and 0.12 eV from the stepped
conformation (No.11 in Fig. S5D). These energies are much smaller than the adsorption energy on Cu (2.6eV) which explains that the crown may become strongly distorted upon adsorption on Cu.

Bd0.4

Free molecule
112°

0.20.030C6090 120 150 180 210Angle [degree]
3. Freezing twoC-C-O-C dihedral

0.3

0.12 V

0.2

stepped

0.8
0.6

0.4

Relative Energy [eV]

Relative Energy [eV]1.00.35 V
0.1
0.00bent

A2

4. Freezing
C-C-O-C dihedral

468Conformation1012

5. Angle set to 140°6. Angle set to 150°

1. Gas phase

2. Freezing
C-C-O-C dihedral

11. Bulk phase

9. Angle set to 170° 8. Angle set to 165° 7. Angle set to 160°
10. Relaxation
without freezing

Figure S5 DFT calculations of Br-CR in gas phase.
(A) Energetically stable bending angle. The angle θ is defined with the model in the inset. (B) Relative
energy between 11 bending structures shown in (C).

UPS and DFT results of work function variation due to Br-CR adsorption on Cu(111).

Xe hν= 8.43 eV

BIntensity [arb. units]

ACu d band

Cu(111)surface state−1.48 eV

4.1 Å BrCR/Cu(111)

WF=4.47 eV

2.1 Å BrCR/Cu(111)

WF=4.69 eV[011]
WF=4.86 eV

[001]

[211]

−1.58 eV 0.1 Å BrCR/Cu(111)

Cu(111)[001]-4.0-3.5-3.0 -2.5 -2.0 -1.5 -1.0 -0.5 0.0[211]
Binding Energy [011]
Binding Energy [eV]WF=4.86 eV

Figure S6 Work function and charge density distribution of Br-CR on Cu(111).
(A) Secondary cutoff of the UPS signals obtained from the bare Cu(111) (black dots), 0.01 ML (graydots), 0.05 ML (blue dots), and 0.25 ML (purple dots) with the Xe Iα 8.43 eV light. Obtained work
functions are 4.86 eV, 4.86 eV, 4.69 eV, and 4.47 eV, respectively. (B) DFT simulation of charge density
map. Yellow (blue) areas denote electron-gain (-deletion) (iso-value = ±0.00036 [e/bohr3]).

SPALEED results of Br-CR film on Cu(111).
EB=41.0 eV

A(00)

B(00)

Figure S7 LEED results obtained on Br-CR film on Cu(111).
This Br-CR film was prepared in a different manner compared to the main manuscript. First, a thick BrCR film was deposited on Cu(111) at 300 K, and the thicker layers were desorbed by subsequentannealing (~500 K). Then, only the interface monolayer film could remain. (A) SPA-LEED image at
41.0 eV. The (00) spot locates at the center. (B) Simulated LEED spots. Observed spots in (A) weremarked as filled circles. Blue, green and red colors are caused by three domains of the Br-CR film. The⃗⃗⃗ = 0.88 nm, ⃗⃗⃗obtained unit cell: 𝑎′𝑏′ = 1.79 nm, = °.